A Iraqi militia leader on Monday threatened to attack American soldiers in the region after the US struck five locations in Iraq and Syria that belong to the Iran-backed Kataib Hezbollah militia in what a senior official described as a "defensive action". The Pentagon said the move was in response to a rocket attack that killed a US civilian contractor and wounded four soldiers in Kirkuk earlier this week. At least 25 militia fighters were killed and 55 wounded after the US strikes, security and militia sources in Baghdad confirmed. US special representative for Iran Brian Hook said the strikes were “defensive action” to protect its troops and said the targets included “command and control” locations for the group. In a call with reporters on Monday, Mr Hook said the US was “working on a mission to restore deterrence in Iraq … lost under nuclear deal” that former US president Barack Obama reached with Iran in 2015 and that the current administration abandoned in 2018. He said US President Donald Trump “has shown great deal of restraint” in addressing continuous attacks by pro-Iran groups in Iraq. Mr Hook estimated there have been at least 11 attacks against joint US-Iraqi bases in the past month. On specific targets for Monday's strikes, Mr Hook said “they included command and control location and weapons storage facilities” that Kataib Hezbollah used to “plot attacks against both US and Iraqis”. The US official stressed the deterrence , he said “the last thing US is looking for is kinetic action in Middle East”. Another senior US official, Assistant Secretary for Near East David Schenker qualified the targets as “significant”, especially the ones on the Syria border. “This was a serious response but in many ways proportionate,” Mr Schenker said. “We don’t want an escalation here, we want a de-escalation.” Mr Schenker said the “Iranians continuously pushed the envelope" in escalating the attacks "until they finally and inevitably killed an American”. “This was not a mistake,” he said of the death of the US contractor in Kirkuk. "We will hold America accountable and will not stay silent on what has happened. The administration in Washington cannot possibly think that they control Iraq," said Abu Mahdi Al Muhandis, a senior member in Iraq’s Popular Mobilisation Forces (PMF). "The response to America will be harsh," he said. The PMF is an umbrella grouping of paramilitary groups that was formally integrated into Iraq's armed forces during the fight against ISIS. Most of the militia in the group are backed by Iran. Mr Al Muhandis, the former head and founder of Kataib Hezbollah, is one of Tehran's most powerful allies in Iraq. His comments were echoed by the Iranian regime, which said the US had shown "support for terrorism" with its actions. "With these attacks, America has shown ... its neglect for the independence and sovereignty of countries and it must accept consequences for its illegal act," government spokesman Abbas Mousavi said. Speaking earlier, US Secretary of State Mike Pompeo said that Washington may take "additional actions" in the region. "We will not stand for the Islamic Republic of Iran to take actions that put American men and women in jeopardy," Mr Pompeo said after briefing US President Donald Trump on the strikes. Mr Pompeo had previously blamed Iranian proxies in the country for an attack on a joint facility in Baghdad on December 9. Populist Iraqi cleric, Moqtada Al Sadr, gave a warning on the consequences of dragging the country in to "an escalating conflict between the US and Iran". "Government officials must take a serious stand to keep Iraq away from a savage war," Mr Al Sadr said. "I'm against Iraq becoming an area of conflict and tension." Lebanon’s powerful Shiite group Hezbollah also condemned the strikes, calling them a "blatant attack on Iraqi sovereignty, security and stability". The group, which is also backed by Iran, criticised the US for attacking groups in Iraq that assisted in defeating ISIS. Iraq's semi-official Human Rights Commission called for "restraint" following the strikes on Iraq. "Everyone should exercise restraint and not drag Iraq into another conflict. Diplomatic methods must be used to stop these violations and abuses," the commission said. Iraq's Parliamentary speaker, Mohammed Al Halbousi, called on Iraqi parties to "exercise restraint and not to escalate violence". Tension is highafter President Donald Trump's administration withdrew the US from a 2015 nuclear agreement between Iran and world powers. Mr Trump said the deal was flawed and he sought a new one that would further curb Iran's nuclear programme, halt its ballistic missile work and end its support for proxies in the region.