WASHINGTON/BAGHDAD (Reuters) - A U.S. service member was killed and several other people were injured when a military helicopter on a mission against Islamic State militants crashed in Iraq late on Sunday, the Pentagon said.

There were no indications the crash was caused by hostile fire and the incident was being investigated, Pentagon spokesman Colonel Robert Manning told reporters on Monday.

Three personnel had been evacuated for medical treatment, Manning said, but he did not disclose their nationalities. He also did not identify the name of the service member who was killed.

“The aircraft was conducting a partnered counter-terrorism mission against ISIS in support of Operation Inherent Resolve,” he added, using an acronym for Islamic State.

Earlier on Monday, Colonel Sean Ryan, a spokesman for the U.S.-led international coalition fighting Islamic State, said on Twitter the crash was of a military helicopter.

On March 15, all seven personnel aboard a U.S. military helicopter carrying American service members were killed in a crash in western Iraq.

The United States says it has about 5,200 troops in Iraq that are part of a coalition fighting Islamic State militants.