The leaders of Britain and Germany joined other American allies Sunday in criticising President Donald Trump's US entry ban for people from seven Muslim-majority countries, even as far-right politicians on the continent celebrated the move.

British Prime Minister Theresa May does “not agree” with Trump's order and will challenge the US government if it has an adverse effect on British nationals, a spokesman said.

The official comment came after May refused to condemn the ban during a visit to Turkey to meet with Turkish leaders. She said in Turkey that the decision was a matter solely for the US.

German Chancellor Angela Merkel also regrets the travel ban

“She is convinced that even the necessary, resolute fight against terrorism doesn't justify putting people of a particular origin or particular faith under general suspicion,” Angela Merkel spokesman Steffen Seibert said.

Merkel raised the issue during a phone call with Trump on Saturday, citing the 1951 Geneva Refugee Convention that calls on signatories to take in people fleeing war, Seibert said.

“The German government will now examine what consequences the US government's measures have for German citizens with dual citizenship and, if necessary, represent their interests toward our American partners,” he said.

An initial joint US-German statement following the call made no mention of the topic of refugees or travel bans.

Among the first leaders to voice criticism was French President Francois Hollande, who said Saturday that “when (Trump) rejects the arrival of refugees, while Europe has done its duty, we should respond to him.”

Nationalist, far-right groups in Europe applaud travel restrictions

Meanwhile, nationalist and far-right groups in Europe applauded the US travel restrictions.

The Dutch anti-Islam populist Geert Wilders said in a tweet: “Well done @POTUS it's the only way to stay safe + free. I would do the same. Hope you'll add more Islamic countries like Saudi Arabia soon.”

Wilders, whose Party for Freedom is polling strongly before the country's March 15 election, later tweeted: “No more immigration from any Islamic country is exactly what we need. Also in The Netherlands. For Islam and freedom are incompatible.”

The far-right National Democratic Party in Germany celebrated what it described as “the massive restriction on the entry of pseudo-refugees and Muslims to the USA.”

“For the first time ever one can say from a nationalist perspective: keep going, USA,” the party wrote on its official Facebook page.

In Italy, the leader of the anti-immigrant Northern League party expressed admiration for Trump's entry ban.

“What Trump's doing on the other side of the ocean, I'd like it done also here,” Matteo Salvini told reporters on the sidelines of a conference.

Referring to the hundreds of thousands of asylum-seekers and economic migrants brought to Italy in the last few years after being rescued in the Mediterranean, Salvini said there is “an invasion underway which needs to be blocked.”

Salvini is pressing for early elections and courting other far-right leaders for a possible campaign coalition.