A Trump administration official has seized on the Westminster terror attack to justify the president’s blocked travel ban, which targets refugees and immigrants from six Muslim-majority countries, despite confirmation that the attacker was neither an immigrant nor a refugee.

Sebastian Gorka, a national security aide to the president and a former editor for the far-right news site Breitbart, told Fox News’s conservative talk show host Sean Hannity on Wednesday evening that the attack in Westminster, that left three people and the attacker dead, “should be a surprise to nobody”.

“The war is real and that’s why executive orders like president Trump’s travel moratorium are so important,” Gorka said.

Despite the official’s remarks it is almost certain that the British-born attacker, 52 year-old Khalid Masood, would not have been affected by Trump’s ban, which targets immigrants and refugees from a handful of countries. Further, the US would have already been entitled to block Masood from the country, given his extensive criminal record.

Trump has issued two executive orders seeking to temporarily bar travel from the selected groups. Both have been blocked by federal courts, which found grounds for a violation of the US constitution that prohibits religious discrimination.

On Wednesday, the administration filed a motion to a federal appeals court requesting an accelerated hearing of the government’s appeal against the most recent legal block on the policy.

Gorka, the presidential adviser, appeared on the same Fox News show as the former Ukip leader and close Trump confident Nigel Farage, who also argued the Westminster attack served as justification for Trump’s ban.

“Surely an American audience seeing this horrendous thing happening in Westminster today should start to say to itself that when Donald Trump tries to put in place vetting measures, he’s doing it to protect your country,” Farage said.

He went on to lambast those who have protested against the executive order, and added: “Frankly, if you open your door to uncontrolled immigration from Middle Eastern countries you are inviting in terrorism.”

Farage’s claims were inaccurate. Since the 9/11 attacks, no immigrant from the six countries targeted by Trump’s travel ban – Sudan, Somalia, Iran, Yemen, Syria and Libya – or any refugee has carried out a deadly terror attack in the US. Refugees resettled in the United States are already subjected to rigorous vetting procedures that take between 18 months to two years to complete.

Mila Johns, an independent counter terrorism researcher and a former analyst at the National Consortium for the Study of Terrorism and Responses to Terrorism, argued the claims made by Gorka and Farage “make absolutely no sense at all”.

“Even if you look at the last time London suffered a major attack, three of the four 7/7 bombers were born in Britain and the other was born in Jamaica – not really a place you think that radicalized Islamists are going to come from.”

“I think facts are something the Trump administration seems to have a very tenuous grasp on, let alone an appreciation for,” Johns added. “It’s incredibly significant if, when confronted with actual facts and evidence, they continue to repeat their own propaganda, that has no relationship to reality.”

Gorka’s comments came shortly after the president’s son, Donald Trump Jr, was labelled “a disgrace” for attacking London mayor Sadiq Khan based on a six-month-old interview with the Independent.

The mayor had said that terror attacks were “part and parcel of living in a big city” and “I want to be reassured that every single agency and individual involved in protecting our city has the resources and expertise they need to respond in the event that London is attacked.” Trump Jnr had partially quoted the article without contextualizing Khan’s remarks.