Iran has instructed its navy to target US ships if they "endanger the security" of Iranian crafts, the head of Iran's Islamic Revolutionary Guards Corps said on Thursday. The retaliatory instruction came a day after US President Donald Trump said he had instructed the US Navy to "shoot down and destroy any and all Iranian gunboats if they harass our ships at sea" following US accusations of harassment by Iranian gunboats in the Arabian Gulf. "We have instructed our military units at sea that if a floating or combat unit from the Navy wants to endanger the security of our non-combat ships or warships, to target that vessel or military unit," Gen Hossein Salami said, according to state-run news outlet ISNA. "We declare to the United States that we are absolutely determined and serious in defending our national security, water borders and maritime interests," he said. Iran and the US have been tussling over who is at fault for a maritime encounter in the north Arabian Gulf on April 16. The US claimed 11 Iranian speedboats “repeatedly conducted dangerous and harassing approaches", but the Iranians denied the claim, saying the US had initiated the incident. The risk of escalation between the US and Iran is particularly high at this point because of the coronavirus pandemic, which has affected both countries severely, said Aniseh Bassiri Tabrizi, a Middle East security expert at the Royal United Service Institute. "On top of the fact that each side has maintained in place its strategy (maximum pressure and retaliation respectively), it is possible that the coronavirus outbreak will increase the chances of miscalculation," Ms Tabrizi told <em>The National</em>. "Iran might think that the US is bluffing and that it will not wish to get embroiled in a military confrontation given the extent of the crisis at home and the overarching commitment of the Trump administration to get out of, not more involved in, the Middle East," she said. "Similarly, the US might think that Tehran is too distracted by Covid at home and try to exacerbate some of the weaknesses Iran has manifested over the past year." The statements being issued by Tehran and Washington are not "mere rhetoric, but rather reflect a desire to showcase resolve to pursue the policy advanced over the past year", Ms Tabrizi said. "Rather than seeing the outbreak as a chance for a detente between and for the reprisal of meaningful diplomacy, so far the coronavirus has thus represented yet another battlefield in the confrontation between Iran and the US." Gen Salami said Iran considered US control over military assets weakened by the distraction of the coronavirus pandemic. "What was observed last week was the turmoil and operational indiscipline in the US military units at sea," he said. Gen Salami was backed by a tweet from Iranian Foreign Minister Javad Zarif, who referenced the number of coronavirus cases within the US military. "US forces have no business 7,000 miles away from home, provoking our sailors off our OWN Persian Gulf shores," Mr Zarif wrote.