OMAHA, Neb. (AP) -- The high-level negotiations over China's export controls of rare earths is giving U.S. businesses some relief, even though it may be only for now.

China has approved "a certain number" of export permits for rare earth elements and related items, its commerce ministry said on Thursday, one day after U.S. President Donald Trump declared that Beijing would supply to the U.S. companies those key elements and the magnets made from them following a two-day trade talk in London.

"I will be one of the happiest people out there if, if in fact, China starts to, to release some of those heavy rare earths and allows them to get into the world economy because the world economy is going to shut down without those heavy rare earths," said Mark Smith, chief executive officer of NioCorp., which is developing a new mine in Nebraska to produce niobium, scandium, titanium and an assortment of rare earths.

Export controls of the minerals apparently eclipsed tariffs in the latest round of trade negotiations between Beijing and Washington, after China imposed permitting requirements on seven rare earth elements in April, threatening to halt production of cars, robots, wind turbines and other high-tech products in the U.S. and around the world.

Negotiators from the two governments said they reached a framework to move forward, with details yet to be agreed to by Trump and Chinese President Xi Jinping, but businesses welcomed the developments, even though uncertainties persist.

Rare earth elements are some of the most sought-after critical minerals. Despite the name, they aren't actually rare, but it is hard to find them in high enough concentrations to make mining them economical. They are also difficult to extract from the ore, and China over the past several decades has built dominance in the processing capacity, supplying nearly 90% of the world's rare earths.

In the heat of the tariff war with Trump, Beijing on April 4 announced permitting requirements for seven heavy rare earths: samarium, gadolinium, terbium, dysprosium, lutetium, scandium and yttrium, citing the need to "better safeguard national security and interests and to fulfill global duties of non-proliferation."

The elements China has restricted, such as terbium and dysprosium, are key ingredients needed to make permanent rare earth magnets withstand high temperatures. That is crucial for a variety of uses in electric vehicles, wind turbines and military uses like jet engines and nuclear submarines.

Some of the other rare earths needed for those magnets are produced at the only operating U.S. rare earths mine run by MP Materials in California, but China remains the only source of nearly all of what's known as the heavy rare earths. MP Materials previously sent the heavy rare earths that it mines to China for processing but it halted that in April amid the tariffs. The company is working to expand its own processing capability as soon as possible, and it is building a new magnet plant in Texas.

Neha Mukherjee, rare earths analyst at Benchmark Mineral Intelligence, had previously predicted that most companies wouldn't start to run short of rare earths until later this year, but it appears some companies already have problems.

"The overall market stockpile exists, but looks like a lot of OEMs (original equipment manufacturers), especially auto manufacturers, were not prepared, especially in Europe," Mukherjee said. Some American companies have stockpiled, but they "might start experiencing constraint if this continues."

"Looks like most of the stockpile is still in China hence the bottleneck in supply," Mukherjee said.

On June 4, the European Association of Automotive Supplies said the industry was "already experiencing significant disruption" due to China's export restrictions on rare earths and magnets. "These restrictions have led to the shutdown of several production lines and plants across Europe, with further impacts expected in the coming weeks as inventories deplete," the group said.

Details are still scarce on any agreement on rare earths shipments from China.

On Thursday, He Yadong, spokesman for the Chinese commerce ministry, said China will "sufficiently consider the reasonable needs and concerns by all countries in the civilian field" in reviewing applications of export permits for rare earths and related items.

He said that it is consistent with international practice to put export controls on rare earths because they can be used for both civilian and military purposes.

In a note, Gabriel Wildau, managing director of the consultancy Teneo, wrote that even though there is an agreement for now, "supply cutoffs will remain an ever-present threat." That's because China's licensing regime for the export of the seven heavy rare earths and related magnets is permanent, despite perceptions at the time that it was an act of retaliation, he wrote.

China "will probably not approve exports in sufficient quantity to allow U.S. customers to stockpile, ensuring that Beijing's leverage remains undiminished," he wrote. "Beijing may approve few if any exports to U.S. defense companies and their suppliers."

Smith of NioCorp. said even if the Chinese are offering a reprieve from their restrictions on rare earths, they will likely still keep limits in place on U.S. military uses.

"If I'm in the military and flying a jet or running a nuclear class submarine or a guided missile, I don't want that to fail because of high temperatures. So we have to have these heavy rare earths," Smith said.

Smith said he hopes to find a solution to the problem of America being almost entirely dependent on China for these elements.

"I sincerely hope from the bottom of my heart that we use this situation as our final learning," Smith said. "Let's take care of what we know needs to be taken care of."