UPDATE 1-Iran mostly likely brought down Ukraine airliner with anti-aircraft missiles -U.S. officials

A Ukraine airliner that crashed in Iran, killing all 176 people aboard, was most likely brought down accidentally by Iranian anti-aircraft missiles, U.S. officials said on Thursday.

According to satellite data, one U.S. official said, the Ukrainian International Airlines Boeing 737-800 bound for Kiev was airborne for two minutes after departing Tehran when the heat signatures of two surface-to-air missiles were detected. That was quickly followed by an explosion in the vicinity of the plane, the official said. Heat signature data then showed the plane on fire as it went down.

Two U.S. officials said Washington believed the downing of the plane, which occurred at a time of rising tensions between Iran and the United States, was accidental. U.S. President Donald Trump said on Thursday the deadly crash could have been a mistake and he did not believe it was a mechanical issue.

The Pentagon declined to comment.