Secretary of State Mike Pompeo said he was responding to Iran's "brinkmanship" of nuclear steps, which have been aimed at pressuring the United States to remove sanctions as called for by the 2015 accord.

"These escalatory actions are unacceptable and I cannot justify renewing the waiver," Pompeo said in a statement.

President Donald Trump bolted from the agreement negotiated under his predecessor Barack Obama, under which Iran had drastically curbed its nuclear activities.

But the Trump administration until now had issued waivers for companies, primarily from Russia, that are still present in Iran to carry out the agreement.

The United States will notably remove the waivers that allowed the modification of the heavy water reactor in Arak, which prevented it from using plutonium for military use, as well as the export of spent and scrap research reactor fuel.

Pompeo said that the United States was issuing a final 60-day waiver to let companies involved in the projects to wrap up their operations.