US expects more attacks from Iran-backed groups: Esper

The Pentagon warned Thursday that the Iran-backed Kataeb Hezbollah group that stormed the US embassy in Baghdad would carry out more attacks on US facilities -- and would regret it.

"The provocative behavior has been out there for months... So do I think they may do something? Yes. And they will likely regret it," Defence Secretary Mark Esper told reporters.

"We are prepared to exercise self-defense, and we are prepared to deter further bad behavior from these groups, all of which are sponsored, directed and resourced by Iran." Several thousand Iraqi protesters attacked the US embassy in Baghdad on Tuesday, breaching its outer wall and chanting "Death to America!" in anger over weekend airstrikes that killed pro-Iran fighters.