President Donald Trump authorised the killing of Iranian Major General Qassem Soleimani seven months ago if Iran's increased aggression resulted in the death of an American, according to five current and former senior administration officials. The presidential directive in June came with the condition that Mr Trump would have final sign-off on any specific operation to kill Maj Gen Soleimani, officials said. That decision explains why assassinating the general was on the menu of options that the military presented to Mr Trump two weeks ago for responding to an attack by Iranian proxies in Iraq, in which a US contractor was killed and four US service members were wounded, the officials said. The timing, however, could undermine the Trump administration's stated justification for ordering the US drone strike that killed Soleimani in Baghdad on 3 January. Officials have said Maj Gen Soleimani, the leader of the Islamic Revolutionary Guard Corps' elite Quds Force, was planning imminent attacks on Americans and had to be stopped. "There have been a number of options presented to the president over the course of time," a senior administration official said - adding that it was "some time ago" that the president's aides put assassinating Maj Gen Soleimani on the list of potential responses to Iranian aggression. After Iran shot down a US drone in June, John Bolton, Mr Trump's national security adviser at the time, urged him to retaliate by signing off on an operation to kill Maj Gen Soleimani, officials said.Secretary of State Mike Pompeo also wanted Mr Trump to authorise the assassination, officials said. But Mr Trump rejected the idea - saying he'd take that step only if Iran crossed his red line: killing an American. The president's message was "that's only on the table if they hit Americans", according to a person briefed on the discussion. Neither the White House nor the National Security Council responded to requests for comment. Mr Bolton and the State Department also did not respond to requests for comment. US intelligence officials had closely tracked Maj Gen Soleimani's movements for years. When Mr Trump came into office, Mr Pompeo, who was Mr Trump's first CIA director, urged the president to consider taking a more aggressive approach to Maj Gen Soleimani after showing him new intelligence on what a second senior administration official described as "very serious threats that didn't come to fruition".