the war against ISIS if he allowed the deployment of a new US special force in the country.

Washington said on Tuesday that it would send troops expected to be about 200 elements to Iraq to carry out raids on the militant group, which seized large areas of Syria and Iraq.

Hours later, al-Abadi said that the deployment of any such force would require consultation with his government as these statements appear to be made for domestic consumption inside.

US Secretary of State , John Kerry said on Wednesday that the Iraqi government has been kept informed of plans as the two governments will hold close consultations on practical details.

However, Abadi's politician partners said that they would never accept an expanded role for American forces and insisted that the prime minister would not dare to act on his own after the withdrawal of parliamentary support from his program of internal reform last month because of concern that extensive consultations have not been enough before making important decisions.

Mohammed Naji MP from Badr Organization and one of the local leaders in the Popular Mobilization Units (PMU) , which includes Shiites and other anti fighters to ISIS said "If Abadi take a single decision approving the deployment of US special forces then we will interrogate him in Parliament. He knows very well that the interrogation could lead to vote in withdrawing confidence" , according to Reuters.

Abadi faced a major challenge in November from within his own ruling coalition when parliament voted unanimously to bar the government from passing important reforms without its approval.

The move, seen as an effort to curb Abadi amid discontent over his leadership style and the slow pace of reforms demanded by protesters, stirred speculation about an attempt to topple him but such fears have lately subsided.

"The government is not allowed to authorize a deployment of American troops in Iraq even if it they are expeditionary or intelligence gathering forces," said Hakim al-Zamili, a leading politician from the Sadrists, a movement founded by anti-American cleric Moqtada al-Sadr.

Ammar Tuma, leader of the Fadhila party in the Shi'ite alliance, backed that position, arguing that only parliament, not Abadi, has the authority to approve the presence of foreign combat forces.

Resistance to any expansion of the U.S. role in the country, no matter how limited or gradual, stems in part from absolute mistrust among Iraqis and their leaders of Washington's intentions.

Naji said he feared that once deployed, U.S. special forces might eventually turn their attention to pursuing Hashid Shaabi (PMU) commanders and key Shi'ite politicians, some of whom are on the U.S. terrorism watch list.

"For Abadi to give a green light for the American troops to deploy in Iraq would not be a shot in the foot," said another lawmaker from the National alliance. "It would be a shot in the head."

MISSION IMPOSSIBLE

Opposition from Shi'ite factions, seen as a bulwark against the Islamic State insurgents posing the biggest security threat to major OPEC oil exporter Iraq since the fall of Saddam Hussein in 2003, could also force Abadi to stall Washington's plans.

The prime minister has been under mounting U.S. pressure to rein in the Iranian-backed armed groups, angering the forces who enjoy support from many of Iraq's majority Shi'ites.

Lawmakers said Abadi would not risk a confrontation with the paramilitaries, but it will be difficult for him to resist pressure from Washington, a major donor to the Iraqi military, to give U.S. troops a wider combat role.

"It's nearly an impossible mission for Abadi to find a compromise. He has to make sure not to provoke his coalition and powerful Hashid groups and at the same time respond to the Americans," said Baghdad political analyst Ahmed Younis.

"If Abadi accepts the deployment of American special troops, he offers his rivals on a silver platter the chance to sack him."

The factions' leaders have already rejected any deployment of U.S. forces and said they would not hesitate to turn their attention from battling Islamic State in order to fight the Americans.

Shi'ite factions put up fierce resistance to the U.S. occupation that followed Saddam Hussein's overthrow.

Jafaar Hussaini, a spokesman for Kata'ib Hezbollah, one of the main Iranian-backed Shi'ite militant groups, said sending U.S. forces would only worsen the security crisis in Iraq.

"Anybody, including Prime Minister Abadi, who approves the presence of American troops in Iraq should bear responsibility for triggering an all-out civil war," he said.

While such warnings may be premature, an increase in direct U.S. military activities - even on a small scale - could fuel instability and undermine chances of containing the sectarian conflict.

The last U.S. troops withdrew in 2011 but some returned as advisers in 2014 after Islamic State's advance threatened Baghdad and they now number around 3,500.

Russia's larger military role in Syria and its participation in a security coordination cell in Baghdad that includes Iran and Syria has raised concerns in Washington that it is losing ground to its former Cold War foe in the Middle East.

Naji, the Badr lawmaker, said deploying U.S. troops to Iraq would be "a magnet" that would attract more meddling by foreign powers.

"We will be a courtyard for other powers to settle their own scores," he said.