Iraq says the United States military air strikes targeting Iraqi paramilitary groups will force it to reconsider its relationship and work with the US-led international anti-Islamic State coalition stationed there.

Iraq’s National Security Council said in a statement on Monday the US air strikes were a violation of sovereignty and that US forces acted based on their own political priorities and conclusions.

Protecting Iraq, its military bases, and all troops stationed there is exclusively the responsibility of Iraqi security forces, the council said.

The US military carried out air strikes on Sunday against the Kataib Hezbollah militia in response to the killing of a US civilian contractor in a rocket attack on an Iraqi military base, officials said.

U.S. forces conducted airstrikes against bases of the Iran-backed Kata’ib Hezbollah group in Iraq and Syria on Sunday, the U.S. Department of Defense said pic.twitter.com/wyUK1eONF7

— QuickTake by Bloomberg (@QuickTake) December 30, 2019

Iraqi sources said at least 25 militia fighters were killed and 55 wounded.

The group, which is a separate force from the Lebanese militant group Hezbollah, has vowed revenge. It operates under the umbrella of the Iraqi state-sanctioned militias known collectively as the Popular Mobilisation Forces. Many of them are supported by Iran.

“Our battle with America and its mercenaries is now open to all possibilities,” Kataeb Hezbollah said in a statement. “We have no alternative today other than confrontation and there is nothing that will prevent us from responding to this crime.”

Iraqi Prime Minister Adel Abdul Mahdi condemned the US air strikes.

“The prime minister described the American attack on the Iraqi armed forces as an unacceptable vicious assault that will have dangerous consequences,” his office said.

The air strikes could plunge Iraq further into the heart of a proxy conflict between Washington and Tehran.

Tensions have risen between Tehran and Washington – Iraq’s two main allies – since last year when President Donald Trump pulled out of a 2015 nuclear deal and reimposed sanctions.

Earlier this month, US Secretary of State Mike Pompeo blamed Iranian-backed forces for attacks on bases in Iraq and said any attacks by Tehran or proxies harming Americans or allies would be “answered with a decisive US response”.

Today I spoke with @UN Secretary-General @antonioguterres following the U.S. response to recent attacks in #Iraq. I made clear that our defensive action was aimed at deterring #Iran and protecting American lives.

— Secretary Pompeo (@SecPompeo) December 30, 2019

US officials said Washington had exhibited patience amid escalating provocations from Iran and its allies, but that it was time to re-establish deterrence against aggression.

“After so many attacks it was important for the president to direct our armed forces to respond in a way that the Iranian regime will understand,” US special representative for Iran Brian Hook said in a news briefing.

Iran denies involvement in attacks on US forces and has condemned the raids as “terrorism”.

“This claim without any evidence cannot justify bombing and killing people in violation of international law,” said Iranian government spokesman Ali Rabiei.

-AAP