Reflecting on his first 100 days of ‘making America great again’, US President Donald Trump has admitted he misses his old life when he could drive a car and wasn’t locked up in the White House “cocoon”.

“I love my previous life. I had so many things going,” Trump told Reuters in an interview published Friday (US time).

“This is more work than in my previous life. I thought it would be easier,” the former New York City real-estate mogul said.

The rare words of humility from the 45^th president of the United States were followed by a rallying speech to mark the 100-day milestone at the National Rifle Association Leadership Forum in Atlanta on Friday.

During the same address, Mr Trump sneeringly referred to Senator Elizabeth Warren as “Pocahontas”, a description many labelled racist, given the widely publicised discussion of her heritage.

Ms Warren, who stumped hard for Hillary Clinton’s failed campaign and is widely tipped to be a contender for the Democratic presidential nomination in 2020, listed herself as a Native American when teaching law at Harvard.

That claim has been criticised, in part because Ms Warren cited her mother’s “high cheekbones” and “family stories” as evidence of American-Indian heritage.

The Snopes fact-check site rated it “undetermined” if she had claimed preferment in university hiring on the basis of an unidentified 19th century ancestor.

Along with talk of protecting the Americans’ right to bear arms, President Trump claimed a 73 per cent decrease in illegal immigration on the southern border of the continent since he took command of the Oval Office.

President Trump said he would still “build the wall” along the Mexican border, repeatedly reassuring the crowd, “don’t even think” he would not.

“We’ve done so unbelievably at the borders already, they’re trying to use this number against us, but you need that wall to stop the human trafficking, the drugs, to stop the wrong people,” he said.

He also appeared to hint at the possibility of a second term, not least by joking at Ms Warren. He told the crowd: “I have a feeling that in the next election you’re going to be swamped with candidates, but you’re not going to waste your time.

“You came through for me, and I am going to come through for you.”

Despite an approval rating below 50 per cent, he has come good on some of his promises, including withdrawing from the Trans-Pacific Partnership trade deal and approving the controversial Dakota Access Pipeline.

Last week Mr Trump pondered the 100-day milestone on Twitter: “No matter how much I accomplish during the ridiculous standard of the first 100 days, & it has been a lot (including S.C.), media will kill,” he told his followers.

However, it’s clear the benchmark matters to Mr Trump, who laid out his ‘Contract with the American Voter’ outlining his ‘100-day action plan’ as President-Elect in 2016.

The leader promised to withdraw from the Trans-Pacific Partnership; remove restrictions on clean coal and shale oil energy resources; increase national security against cyber-related attacks; investigate “abuses of visa programs”  and impose a five-year ban on officials lobbying after leaving the administration.

On a more personal level, Mr Trump told Reuters he missed aspects of his old life.

“You’re really into your own little cocoon, because you have such massive protection,” he said. “I like to drive … I can’t drive anymore.”