The president of the USA Joe Biden sent a clear message to Iran’s supreme religious leader, Ayatollah Ali Khamenei, warning against targeting US forces in the Middle East region, the White House said, after the attacks on American soldiers in Iraq and Syria.

“He was given a clear message,” White House spokesman John Kirby told reporters, declining to elaborate.

American officials are worried on the possibility of an extension of the conflict in the Middle East after Hamas attacked Israel on October 7. The Pentagon is stepping up surveillance of the area and deploying additional forces there. Last week alone, US forces were targeted at least 12 times in Iraq and four more in Syria, according to the US Department of Defense.

On Wednesday, Biden said he warned the ayatollah that the U.S. would respond if the targeting of U.S. forces continued, but did not specify how this message was conveyed to Tehran.