Iran has accelerated its enrichment of nuclear-grade uranium, according to the head of the U.N. atomic watchdog group IAEA.

Yukiya Amano, who is tasked with ensuring that Iran complies with the terms of the Iran nuclear deal, reported that the country has made good on its threat to ramp up the uranium enrichment process. Amano also said that it was unclear when Iran would reach the 300kg stockpile limit set by the deal. “I am worried about increasing tensions over the Iranian nuclear issue,” he said, adding he hoped “that ways can be found to reduce current tensions through dialogue. It is essential that Iran fully implements its nuclear-related commitments.”

America’s withdrawal from the Iran nuclear deal last year created a highly volatile situation in the region, as Iran’s incentive not to continue building nuclear weapons left with the United States. President Donald Trump hopes to negotiate a “better deal” with Iran that would include regulations on its ballistic missile program, as well as a reduction in the troops that the county lends to various regional causes.

In order to pressure Tehran into accepting a new deal with the United States, Trump has reimposed sanctions on the country, barring all American companies from doing business with Iran. The real bite of the United States’ withdrawal from the deal is that Trump has promised to economically isolate any company or country that does business with Tehran, using its muscle to ensure that Iran really feels the pain of noncompliance.

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So far the country has shown no signs that it will give in to the pressure of the United States, instead hoping that by using its nuclear program as a threat it can force the other world powers, and maybe America, to provide economic support. While Iran has yet to actually transgress the regulations of the deal, which is still recognized by China, Russia, the United Kingdom, France and Germany, their recent nuclear enrichment increases are a way of threatening the remaining signatories into finding a way to finance them soon.