The United States has allowed Russian, Chinese and European companies to continue their work at Iranian nuclear sites to make it harder for Tehran to develop nuclear weapons, the US State Department said this week. The US issued waivers to sanctions for non-American companies dealing with Iran's Atomic Energy Organisation. The move by the Trump administration, which in 2018 withdrew from the 2015 Iran nuclear deal and reimposed sanctions on Iran, will allow non-proliferation work to continue at the Arak heavy-water research reactor, the Bushehr nuclear power plant, the Tehran Research Reactor and other nuclear initiatives. As part of its "maximum pressure" campaign, the United States not only restored sanctions it had removed under the nuclear deal but has tightened them to try to force Iran to curb its nuclear, missile and regional activities. But the Trump administration has repeatedly waived the sanctions related to nonproliferation work with Iran, saying such projects are designed to make the Iranian nuclear programme less capable of producing weapons. "As President Trump said earlier this year, Iran will never be allowed to have a nuclear weapon," said US State Department spokeswoman Morgan Ortagus. "We will continue to closely monitor all developments in Iran's nuclear programme and can adjust these restrictions at any time." The waivers were renewed for 60 days. Iran has been pushing for the US to drop sanctions in the face of the country's coronavirus crisis, which has killed 2,898 people and infected more than 44,606. Iran says the US measures are hampering the response, a claim Washington denies. While Washington has offered unconditional aid, officials have said they will not drop sanctions. "Stop lying ... It's not the sanctions. It's the regime," Ms Ortagus said on Monday in a Twitter post that copied a tweet by Iran's Foreign Minister Javad Zarif accusing Washington of waging an economic war on Iranians and engaging in "medical terror" amid the outbreak. Washington has ramped up its pressure campaign in recent days. Last week, it blacklisted five Iran and Iraq-based companies and 15 people for supporting terrorist groups, its third round of sanctions on Iranian targets in two weeks. Under the 2015 deal between Iran and six world powers – Britain, China, France, Germany, Russia and the United States – Tehran agreed to limit its nuclear programme in return for the lifting of sanctions that had hurt its economy. Tehran has long rejected Western assertions that it has sought to develop nuclear weapons.