In his first sit-down news interview since winning a second presidency in November’s election, Donald Trump renewed promises to pardon his supporters involved in the attack on the US Capitol in early 2021.

He also doubled down on promises of mass deportations and tariffs in the conversation with NBC’s Meet the Press host Kristen Welker – the latter of which he acknowledged could cause Americans to pay more after riding voters’ complaints about higher prices back to the White House at the expense of Vice-President Kamala Harris.

“I’m going to be acting very quickly. First day,” Trump said in the interview, claiming convicted Capitol attackers had been put through a “very nasty system”.

“I know the system,” said Trump, himself convicted in May by New York state prosecutors of criminally falsifying business records to conceal hush-money payments to adult film actor Stormy Daniels. “The system’s a very corrupt system.”

Trump said there may be some exceptions to his pardons over an attack on the Capitol that was meant to keep him in the Oval Office after losing the 2020 presidential election to Joe Biden – and which was linked to multiple deaths, including the suicides of traumatized law enforcement officers. He referenced previously debunked claims of anti-Trump law enforcement infiltrating his supporters’ ranks and agitating the attack.

When Trump was asked about Capitol attackers who assaulted police officers he said that “they had no choice”. He also claimed individuals were pressured into accepting guilty pleas.

“Their whole lives have been destroyed,” said Trump, who criticized the outgoing president’s recent pardon of his son, Hunter Biden, on convictions of lying on gun ownership application forms as well as tax evasion. “They’ve been destroyed.”

Trump denied he would direct his second administration’s appointees to arrest elected officials involved in the investigation of the attack on the US Capitol, which led to federal criminal charges against him that have been dismissed. But he made it a point to tell Welker: “Honestly, they should go to jail.”

More than 1,250 people have been convicted or pleaded guilty in the January 6 attack on the US Capitol. And at least 645 people have been sentenced to serve some time in prison, ranging from a few days to 22 years.

During his sentencing Friday, Philip Sean Grillo of New York City, one of the Capitol attackers, tauntingly told the federal judge presiding over his case, “Trump’s gonna pardon me anyways.” Grillo received a one-year prison sentenced and was ordered to be taken into custody immediately.

Another of the convicted attackers, Edward Kelley of Tennessee, was found guilty at trial in November of conspiracy to murder federal employees. Jurors determined he had developed a list of officials he wanted to kill for investigating him in connection with the Capitol attack.

In other parts of Sunday’s interview, Trump reaffirmed his plans to enact tariffs on imports from some of the US’s biggest trading partners. He said he could not guarantee US families would not pay more as a result of his plan.

He also doubled down on refusing to admit Biden fairly defeated him in the 2020 election, claiming he won in November against Harris because the race “was too big to rig”.

On his plans of mass deportations, Welker asked Trump about families with mixed immigration statuses. Trump suggested immigrants living in the US legally were at risk if they had family members living in the country without permission.

“I don’t want to be breaking up families, so the only way you don’t break up the family is you keep them together and you have to send them all back,” Trump said.

He did claim to have some support for working with Democrats to protect Dreamers, or people who have lived in the US for years after being brought to the country as undocumented children. But, as he has done before, he promised to work to end birthright citizenship and said he would consider pushing to amend the US constitution to do so.

“We have to end it,” Trump said.

Welker also asked Trump if he had fully developed a plan to overhaul healthcare after saying he had “concepts” of one during his lone debate with Harris.

“We have concepts of a plan that would be better,” Trump replied, in part.