WASHINGTON: A day after US President Donald Trump ordered no-visa policy for seven Muslim states, a White House official hinted that the ban could be extended to other countries, including Pakistan.

“You can point to other countries that have similar problems like Pakistan and others – perhaps we need to take it further,” White House chief of staff Reince Priebus told CBS News. “But for now, immediate steps, pulling the Band-Aid off, is to do further vetting for people traveling in and out of those countries.”

In the most sweeping use of his presidential powers since taking office a week ago, Trump signed an executive order on Friday to pause the entry of travellers from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for at least 90 days.

The travel curbs began immediately, causing confusion for would-be travellers with passports from the seven countries.

Defending the US President widely denounced order, Priebus said, “This is not a Muslim ban” on the TV programme Face the Nation.

He said Trump has solely identified countries where terrorism is taking place and could lead to danger in the US.

“All this is identifying the seven countries – and the reason we chose those seven countries is those were the seven countries that both the Congress and the Obama administration identified as being the seven countries that were most identifiable with dangerous terrorism taking place in their country.”

The move, implemented immediately by authorities, precipitated large protests across major airports nationwide. The ensuing mobilisation against the order could herald a protracted battle shaping up between migrant advocates and the Trump administration.

While a federal judge has blocked part of the temporary immigration ban, the issue may end up before the Supreme Court, which has not ruled on a similar issue since the 1882 Chinese Exclusion Act.

Trump fought back on Sunday amid growing international criticism, outrage from civil rights activists and legal challenges over his abrupt order for a halt on arrivals of refugees and people from seven Muslim-majority countries.

In his most sweeping action since taking office on January 20, Trump, a Republican, put a 120-day hold on Friday on allowing refugees into the country, an indefinite ban on refugees from Syria and a 90-day bar on citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.

“Our country needs strong borders and extreme vetting, now. Look what is happening all over Europe and, indeed, the world – a horrible mess!” Trump wrote on Twitter on Sunday. “Christians in the Middle-East have been executed in large numbers. We cannot allow this horror to continue!” added Trump, who has presented the policy as a way to protect Americans from the threat of “Islamist militants”.

Civil rights and faith groups, activists and Democratic politicians have promised to fight the order, which caused chaos and confusion for affected travelers and sparked protests at several US airports throughout Saturday.

US Senate Majority Leader Mitch McConnell, a Republican, voiced muted criticism. Speaking on ABC’s “This Week” program, he said it was a good idea to tighten the vetting of immigrants, but “it’s important to remember that some of our best sources in the war against radical Islamic terrorism, are Muslims, both in this country and overseas … We need to be careful as we do this.” A Republican colleague in the Senate, John McCain, was more critical, saying the order had been a confused process and could give Islamic State propaganda material.