JEDDAH/GENEVA -  The Organisation of Islamic Cooperation warned on Monday that the travel ban imposed by US President Donald Trump would strengthen the position of extremists worldwide.

"Such selective and discriminatory acts will only serve to embolden the radical narratives of extremists and will provide further fuel to the advocates of violence and terrorism," said the OIC in a statement.

The 56-member organisation urged the US to reconsider its "blanket decision" and to "maintain its moral obligation to provide leadership and hope at a time of great uncertainty and unrest in the world."

"As a result of this ban many of those fleeing war and persecution have been adversely and unjustly affected," said the Jeddah-based organisation.

An executive order signed by Trump on Friday suspended the arrival of all refugees for a minimum of 120 days, Syrian refugees indefinitely and bars citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days.

US President Donald Trump's travel ban on citizens from mainly Muslim countries is illegal and "mean-spirited", the United Nations human rights chief Zeid bin Ra'ad Zeid al-Hussein said on Monday.

Zeid, who rarely communicates on Twitter, said in a tweet that "discrimination on nationality alone is forbidden under human rights law", adding that "the US ban is also mean-spirited and wastes resources needed for proper counter-terrorism."

The UN bodies most directly engaged with migration - the UN refugee agency and the International Organization for Migration (IOM) - issued a statement on Saturday which made no mention of the executive order and stopped far short of condemning it.

Instead, the agencies urged the US to "continue its strong leadership role and long tradition of protecting those who are fleeing conflict and persecution."

They also vowed "to engage actively and constructively with the US Government... to protect those who need it most".

Iraq parliament votes in favour of tit-for-tat move

Iraqi lawmakers voted Monday to call on the government to enact a reciprocal travel ban on Americans if Washington does not withdraw its decision to bar the entry of Iraqis.

The call is a response to President Donald Trump's executive order barring citizens of Iraq, Iran, Syria, Sudan, Somalia, Libya and Yemen from entering the US for at least 90 days, a move he billed as an effort to make America safe from "radical terrorists".

The travel restrictions, which come on the heels of repeated assertions by Trump that the US should have stolen Iraq's oil before leaving in 2011, risk alienating the citizens and government of a country fighting against militants the president has cast as a major threat to America.

Parliament called on the Iraqi government to "respond in kind to the American decision in the event that the American side does not withdraw its decision", a parliamentary official who was present for the vote told AFP, quoting text of the decision that was read at the session.

"Parliament voted by majority on calling on the Iraqi government and the foreign ministry to respond in kind," MP Hakim al-Zamili said.

Sadiq al-Laban, another lawmaker, confirmed that "the vote was for a call on the government" to enact reciprocal measures.

"We are against this stance from the new administration," Laban said, adding: "We hope that the American administration will rethink... this decision."

Trump's decision led to the detention of incoming refugees at US airports, sparking protests, legal challenges and widespread condemnation from rights groups.

And it has led to a growing backlash inside Iraq that could undermine relations between Baghdad and the US amid the battle for Mosul, the largest military operation yet in the war against the Islamic State group.

The parliamentary vote came a day after its foreign affairs committee made a similar call for Iraq to respond in kind to the US measure.

Hassan Shwairid, the deputy head of the committee, said that the call did not apply to the thousands of American military personnel in the country as part of the US-led coalition against IS.

But US Senators John McCain and Lindsay Graham said Trump's ban would impact military cooperation and security in other ways.

"This executive order bans Iraqi pilots from coming to military bases in Arizona to fight our common enemies," the two lawmakers said in a joint statement.

"Ultimately, we fear this executive order will become a self-inflicted wound in the fight against terrorism," they said.

The Hashed al-Shaabi, a powerful paramilitary umbrella organisation that includes Iran-backed Shiite militias that fought against American forces in past years, called Sunday for US citizens to be banned from the country.

Both units from the Hashed and American troops are deployed in the Mosul area as part of the operation to retake the city from IS, and heightened anti-US sentiment among militiamen could increase the danger to Washington's forces.

Trump's travel restrictions also drew condemnation from populist Shiite cleric Moqtada al-Sadr, America's bete noir for much of its 2003-2011 war in Iraq.

"Get your nationals out before removing expatriates," said Sadr, scion of a powerful clerical family who rose to widespread fame due to his condemnation of and violent resistance to the US invasion and occupation of Iraq.