Trump says any country that buys oil from Iran will not be allowed to do business with U.S.

President Donald Trump said Thursday any country or person that buys oil or petrochemicals from Iran will not be allowed to do any business with the U.S.

U.S. crude oil futures rose $1.11, or 1.91%, to $59.32 per barrel, while global benchmark Brent was up $1.15, or 1.88%, to $62.21 per barrel. Iran is one of the biggest oil producers in OPEC.

“Any Country or person who buys ANY AMOUNT of OIL or PETROCHEMICALS from Iran will be subject to, immediately, Secondary Sanctions,” Trump said in a post on his social media platform Truth Social. “They will not be allowed to do business with the United States of America in any way, shape, or form.”

Trump has implemented what he calls a “maximum pressure” campaign against Iran since taking office, which aims to completely shut down the Islamic Republic’s oil exports. The president has accused Iran of using oil revenue to finance militant groups throughout the Middle East.

Trump also initiated negotiations with Iran last month over its nuclear program. His administration believes Iran is trying to develop a nuclear bomb, an allegation that Tehran has denied. The president has said he would prefer to reach a deal with Iran. During his first term, Trump pulled the U.S. out of the nuclear agreement negotiated with Iran by President Barack Obama.

Trump’s comments are clearly directed at China, which is importing more than 1 million barrels per day from Iran, said Scott Modell, CEO of consulting firm Rapidan Energy. Modell said U.S. sanctions are unlikely to have an impact on Iranian oil flowing to China unless the White House targets Beijing’s state-owned enterprises and infrastructure.

The president’s statements Thursday “don’t signify a change in the administration’s drive to reach a new deal with Iran but rather underscore Trump’s belief in negotiating through strength,” Modell, a former CIA officer, told CNBC.