The US says its forces have carried out strikes in Iraq on three facilities used by Iran-backed militia.
The “proportionate” strikes targeted “Kataib Hezbollah militia group and other Iran-affiliated groups” according to Defence Secretary Lloyd Austin.
He said the precision strikes were “in direct response” to attacks against US and coalition allies in Iraq and Syria.
But a senior Iraqi official said they were a “flagrant violation of Iraq’s sovereignty”.
Iraq’s National Security Adviser Qassem al-Aaraji added that the US strikes did not help bring calm.
Last week, some US military personnel were injured in a missile attack on an airbase in western Iraq.
US officials said they were “undergoing evaluation for traumatic brain injuries”.