NEW YORK (AP) -- Long-threatened tariffs from U.S. President Donald Trump have plunged the country into a trade war abroad -- all while on-again, off-again new levies continue to escalate uncertainty.

Since taking office less than two months ago, Trump has rolled out hefty import taxes on goods coming from America's three biggest trading partners -- Mexico, Canada and China -- and promises that more targets are on the horizon.

Trump is no stranger to tariffs. He also launched a trade war during his first term in office, but has more sweeping plans now. Economists stress there could greater consequences on businesses and economies worldwide this time -- and that higher prices will likely leave consumers footing the bill.

There's also been a sense of whiplash from Trump's back-and-forth tariff threats and responding retaliation, including recently-postponed levies for some goods from Canada and Mexico that followed a 30-day pause for the auto industry. The uncertainty has roiled financial markets, lowered consumer confidence, and enveloped many businesses with questions that could delay hiring and investment.

Here's a timeline of how we got here:

Trump launches a trade war during his first term in office -- taking particular aim at China.

The two countries exchange a series of tit-for-tat levies affecting hundreds of billions of dollars' worth of goods. The dispute centers around U.S. allegations that China deploys underhanded tactics -- including stealing trade secrets and pressuring U.S. companies to hand over sensitive technology -- in an effort to supplant the U.S. in advanced fields such as quantum computing and automated cars.

Trump puts tariffs on most Chinese goods. Meanwhile, Beijing responds with its own retaliatory tariffs on U.S. products ranging from fruit, soybeans and wine to aircraft, automotive and chemical imports.

Separately, Trump slaps tariffs on imported solar panels and washing machines. And in 2018, he imposes taxes of 25% on imported steel and 10% on aluminum imports on national security grounds, escalating tensions with other trading partners. He also uses the threat of more tariffs to force Canada and Mexico to renegotiate a North American trade pact, called the U.S.-Mexico-Canada Agreement, in 2020.

President Joe Biden largely preserves most of the tariffs Trump previously enacted against China, but his administration claims to take a more targeted approach.

In October 2022, he issues sweeping new restrictions on selling semiconductors and chipmaking equipment to China. These curbs will be expanded in October 2023 and December 2024 -- when China responds with a ban of U.S. exports for various high-tech materials like gallium and germanium.

Biden also hikes tariffs on Chinese electric vehicles, solar cells, steel, aluminum and medical equipment in May 2024. And in July, he imposes tariffs on steel and aluminum shipped from Mexico but made elsewhere in an attempt to stop China from circumventing import taxes.

Biden's 2024 tariff moves come in the middle of a heated presidential campaign -- with both Biden and Trump taking jabs at each other in attempts to show who's tougher on China.

On the campaign trail, Trump says that he plans to impose tariffs of at least 60% on all Chinese imports if he wins a second term. He also floats the idea of a tariff of up to 20% on everything else the U.S. imports while threatening to impose even bigger levies for specific countries or manufacturers that take their business outside the U.S.

While the Biden-Harris administration uses tariffs to target China, both Biden and Vice President Kamala Harris -- who becomes the Democratic nominee after Biden drops out of the race -- maintain that Trump's promise of more broad tariffs worldwide would be a mistake. Harris labels Trump's call for tariffs as a "national sales tax" -- with her campaign later saying that a 20% tariff applied across the board would raise expenses for a typical family by almost $4,000 annually.

Trump wins the U.S. presidential election. He continues to promise steep tariff hikes in the coming weeks and months leading up to his first day back in office.

Trump is sworn in. In his inaugural address, he again promises to "tariff and tax foreign countries to enrich our citizens." And he reiterates plans to create an agency called the External Revenue Service, which has yet to be established.

On his first day in office, Trump also says he expects to put 25% tariffs on Canada and Mexico starting on Feb. 1, while declining to immediately flesh out plans for taxing Chinese imports.

Trump threatens 25% tariffs on all Colombia imports and other retaliatory measures after President Gustavo Petro's rejects two U.S. military aircraft carrying migrants to the country, accusing Trump of not treating immigrants with dignity during deportation.

In response, Petro also announces a retaliatory 25% increase in Colombian tariffs on U.S. goods. But Colombia later reversed its decision and accepted the flights carrying migrants. The two countries soon signaled a halt in the trade dispute.

Trump signs an executive order to impose tariffs on imports from Mexico, Canada and China -- 10% on all imports from China and 25% on imports from Mexico and Canada starting Feb. 4. Trump invoked this power by declaring a national emergency -- ostensibly over undocumented immigration and drug trafficking. The levies on Canada and Mexico threaten to blow up Trump's own USMCA trade deal, which allowed many products to cross North American borders duty free.

The action prompts swift outrage from all three countries, with promises of retaliatory measures.

Trump agrees to a 30-day pause on his tariff threats against Mexico and Canada, with both trading partners taking steps to appease Trump's concerns about border security and drug trafficking.

Trump's new 10% tariffs on all Chinese imports to the U.S. still go into effect. China retaliates the same day by announcing a flurry of countermeasures, including sweeping new duties on a variety of American goods and an anti-monopoly investigation into Google.

China's 15% tariffs on coal and liquefied natural gas products, and a 10% levy on crude oil, agricultural machinery and large-engine cars imported from the U.S., take effect Feb. 10.

Trump announces plans to hike steel and aluminum tariffs. He removes the exemptions from his 2018 tariffs on steel, meaning that all steel imports will be taxed at a minimum of 25%, and also raises his 2018 aluminum tariffs to 25% from 10% set to go into effect March 12.

Trump announces a plan for "reciprocal" tariffs -- promising to increase U.S. tariffs to match the tax rates that other countries charge on imports "for purposes of fairness." Economists warn that the reciprocal tariffs, set to overturn decades of trade policy, could create chaos for global businesses.

Beyond China, Canada and Mexico, he indicates that additional countries, such as India, won't be spared from higher tariffs. And in the following weeks, Trump suggests that European countries could face a 25% levy as part of these efforts.

Trump signed an executive order instructing the Commerce Department to consider whether a tariff on imported copper is needed to protect national security. He cites the material's use in U.S. defense, infrastructure and emerging technologies.

Trump signs an additional executive order instructing the Commerce Department to consider whether tariffs on lumber and timber are also needed to protect national security, arguing that the construction industry and military depend on a strong supply of wooden products in the U.S.

Trump's 25% tariffs on imports from Canada and Mexico go into effect, though he limits the levy to 10% on Canadian energy. He also doubles the tariff on all Chinese imports to 20%.

All three countries promise retaliatory measures. Canadian Prime Minister Justin Trudeau announces tariffs on more than $100 billion of American goods over the course of 21 days. And Mexican President Claudia Sheinbaum says her country would respond with its own retaliatory tariffs on U.S. goods without specifying the targeted products immediately, signaling hopes to de-escalate.

China, meanwhile, imposes tariffs of up to 15% on a wide array of key U.S. farm exports. It also expands the number of U.S. companies subject to export controls and other restrictions by about two dozen.

Trump grants a one-month exemption on his new tariffs impacting goods from Mexico and Canada for U.S. automakers. The pause arrives after the president spoke with leaders of the "Big 3" automakers -- Ford, General Motors and Stellantis.

In a wider extension, Trump postpones 25% tariffs on many imports from Mexico and some imports from Canada for a month. But he still plans to impose "reciprocal" tariffs starting on April 2.

Trump credited Sheinbaum with making progress on border security and drug smuggling as a reason for again pausing tariffs -- and the Mexican president said in a post on X that she and Trump "had an excellent and respectful call in which we agreed that our work and collaboration have yielded unprecedented results."

Trump's actions also thawed relations with Canada somewhat, although outrage and uncertainty over the trade war remains. Still, after its initial retaliatory tariffs of $30 billion Canadian (US$21 billion) on U.S. goods, the government said it had suspended its second wave of retaliatory tariffs worth $125 billion Canadian (US$87 billion).

China retaliates against Trump's tariffs by imposing additional 15% taxes on key American farm products, including chicken, pork, soybeans and beef. The escalating trade tensions push stocks lower on Monday as investors worry about the pain Trump's trade wars risk inflicting on the American economy.

The Chinese tariffs were a response to Trump's decision to double the levy on Chinese imports to 20% on March 4. China's Commerce Ministry had earlier said that goods already in transit would be exempt from the retaliatory tariffs until April 12.