Trump sets 'red line' for Tehran amid mounting risks

President Donald Trump's order for airstrikes on a Tehran-backed Iraqi militia group, after resisting retaliating against Iran for months, sent a clear message Sunday that killing Americans was his red line.

US President Donald Trump answers questions from reporters after making a video call to the troops stationed worldwide at the Mar-a-Lago estate in Palm Beach Florida, on December 24, 2019. [Photo: Nicholas Kamm/AFP]

US officials said Monday that Trump had exercised "strategic patience" during the past year in the face of Iran's military activities in the region.

But they said that the death of a US civilian contractor in Kirkuk in a rocket attack by the Hezbollah Brigades on Friday forced Trump's hand.

At least 25 members of the group were killed in retaliatory US strikes Sunday on five of their bases in Iraq and Syria.