Iraq 'studies legal options' over US air raid on militias
The cabinet, headed by Prime Minister Mustafa Al-Kadhimi, held an emergency security meeting the day after the US airstrikes.
Al-Kadhimi condemned the attack as a "blatant and unacceptable violation of Iraqi sovereignty and Iraqi national security".
"Iraq reiterates its refusal to be an arena for settling scores," he added in a statement, urging all sides to avoid any further escalation.
It was a rare criticism of US action by the government of Al-Kadhimi, who is seen as friendly to the United States and has tried to check the power of Iran-aligned militias.
Iraqi officials say they want to avoid being dragged into a tit-for-tat escalation between Washington and Tehran.
For its part, the Popular Mobilisation Forces (PMF), an Iraqi state-supported paramilitary alliance that includes several Iranian proxies and has become the main power broker in Baghdad, said the strikes killed four of its fighters in the Qaim region, some 13 kilometres (eight miles) away from the border.
The fighters were stationed there to prevent jihadists from infiltrating Iraq, the group said in a statement, denying that they had taken part in any attacks against US interests or personnel.
"We reserve the legal right to respond to these attacks and hold the perpetrators accountable on Iraqi soil," the PMF said.
Meanwhile, US Secretary of State Antony Blinken said on Monday that strikes on pro-Iran fighters in Iraq and Syria should send a "strong" message of deterrence not to keep attacking US forces.
"I would hope that the message sent by the strikes last night will be heard and deter future action," Blinken told reporters on a visit to Rome.
"This action in self-defence to do what's necessary to prevent further attacks sends a very important and strong message," he said.
The Pentagon announced that three military facilities used by Iran-backed militia had been hit overnight Sunday to Monday - two in Syria and one in Iraq.
It said the targets had been used by "Iran-backed militias that are engaged in unmanned aerial vehicle (UAV) attacks against US personnel and facilities in Iraq".
Asked in Rome if the United States was holding Iran responsible for the attacks, Blinken said: "A number of the groups involved in recent attacks are militia that are backed by Iran."
The airstrikes on the Iraq-Syria border area were the second attacks ordered by President Joe Biden in response to strikes on US forces in Iraq.