London’s newly elected Muslim mayor Sadiq Khan on Tuesday slammed Republican presidential candidate Donald Trump’s “ignorant” view of Islam after the real estate billionaire, who has called for a temporary ban on Muslims entering the U.S., suggested he would make an exception for Khan.

Trump’s view “could make both our countries less safe — it risks alienating mainstream Muslims around the world and plays into the hands of the extremists,” Khan said in a statement.

“There will always be exceptions,” the New York Times on Monday quoted Trump as saying when asked how his controversial proposal would apply to Khan.

London’s mayor is the son of a Pakistani immigrant bus driver and a seamstress. He was sworn in as London’s mayor on Saturday.

Trump said he was “happy” to see Khan elected, the Times reported, adding: “You lead by example, always lead by example. If he does a good job … that would be a terrific thing.”

Trump has been criticized for his proposed ban, which he announced soon after attacks were carried out by militants in Paris and California last year.

Muslim and human rights groups, Trump’s Democratic rivals and many of his Republican presidential opponents said the proposal was divisive, counterproductive and contrary to American values.

Khan, the Labour Party candidate, defeated his Conservative rival by a record margin to secure the biggest individual mandate in British political history after an acrimonious campaign.

Khan, 45, won despite a concerted, and controversial, campaign by Conservative rival Zac Goldsmith to taint him with ties to Islamic extremists.

London’s previous Labour mayor, Ken Livingstone, was suspended last month from the party after he claimed that Adolf Hitler had supported the Zionist aim of establishing Israel.

Speaking of the Conservatives’ tactics, Khan told Britain’s Observer newspaper: “They used fear and innuendo to try to turn different ethnic and religious groups against each other – something straight out of the Donald Trump playbook.”

In an interview with Time magazine, Khan said he wanted to go to the United States to see the interesting programs the mayors of New York and Chicago were implementing, but that he would have to visit before January in case Trump won the Nov. 8 election.

“If Donald Trump becomes the president I’ll be stopped from going there by virtue of my faith, which means I can’t engage with American mayors and swap ideas,” Khan said.