Iraqi lawmakers voted on Monday to call on the government to enact a reciprocal travel ban on Americans after Iraqis were barred from entering the United States, MPs said.

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 U.S. for at least 90 days, a move he billed as an effort to make America safe from "radical Islamic terrorists".

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 also 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 U.S. ban is also mean-spirited and wastes resources needed for proper counter-terrorism."

Trump on Friday signed an executive order suspending the arrival of all refugees for at least 120 days, Syrian refugees indefinitely -- and barring citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days.

The measures introduced a week after his inauguration were fiercely criticised over the weekend, although UN reactions were largely tepid.

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".