Iran is ready for a prisoner exchange with the United States, Iranian government spokesman Ali Rabiei was quoted as saying on Sunday. "We are ready to exchange Iranian and American prisoners and we are prepared to discuss this issue, but the Americans have not responded yet," Mr Rabiei said, according to the Khabaronline news website. "We are worried about the safety and health of Iranians in jail ... We hold America responsible for Iranians' safety amid the new coronavirus outbreak," he said. In a rare act of cooperation between two foes, the US and Iran swapped prisoners in 2019. American graduate student Xiyue Wang, detained for three years on spying charges, and imprisoned Iranian stem cell researcher Massoud Soleimani, accused of sanction violations, were released. Tehran and Washington have grown more hostile towards each other since 2018, when President Donald Trump pulled the US out of Iran's 2015 nuclear deal with major powers and re-imposed sanctions on Tehran that has crippled its economy. "There is no need for a third country to mediate between Iran and America for the prisoner exchange," Mr Rabiei said. Three Iranian officials told Reuters last week that a prisoner swap between the two countries was in the works. Michael White, a US Navy veteran who has been detained in Iran since 2018, was a likely candidate to be swapped. He was released from prison in mid-March on medical leave but remains in Iran. The United States is set to deport Iranian professor Sirous Asgari, who was acquitted of stealing trade secrets, once he receives medical clearance to leave, US and Iranian officials said on Tuesday.