(CNN) -- The US increasingly believes that Iran mistakenly shot down a Ukrainian airliner on Wednesday, according to multiple US officials. The working theory is based on continuing analysis of data from satellites, radar and electronic data collected routinely by US military and intelligence. The flight crashed following Iranian strikes on US forces in Iraq. President Donald Trump on Thursday said he suspected the crash was not due to mechanical issues, indicating that "somebody could have made a mistake on the other side. "