The White House says “all options remain on the table” for the United States to take military action against Iran, reiterating that Tehran would face “grave consequences” if the killings of antigovernment protesters continue.During a news conference on Thursday, White House Press Secretary Karoline Leavitt said US President Donald Trump and his team had communicated to Iran that “if the killing continues, there will be grave consequences”.Recommended Stories list of 3 itemsend of list“The president understands today that 800 executions that were scheduled and supposed to take place yesterday were halted,” Leavitt told reporters, without providing any evidence to back up the claim that the executions were stopped.“The president and his team are closely monitoring this situation, and all options remain on the table for the president,” she added.Her comments come just hours after Trump appeared to soften his tone after several days of threats against Iran, with the US president saying his administration would take military action against Tehran if more killings were carried out.Thousands of Iranians have taken to the streets since late December last year in mass demonstrations that were sparked by soaring inflation and the steep devaluation of the local currency.The protests have spread to cities and towns across Iran, and activist groups say more than 1,000 demonstrators have been killed in the unrest.The Iranian government, which describes the protesters as armed rioters backed by the US and its major regional ally, Israel, has said more than 100 security officers have been killed in attacks during the demonstrations. Advertisement Al Jazeera is n …