Left-wing congresswoman Alexandria Ocasio-Cortez on Sunday refused to endorse Joe Biden for another run at the White House, adding to growing anxiety in Democratic circles over the president’s ability to run in and win the 2024 election.

The powerful progressive New Yorker said she could not commit to supporting Biden during an appearance on CNN’s State of the Union, saying she was more focused on trying to preserve Democrats’ congressional majority in November’s midterms.

“We’ll cross that bridge when we get to it,” Ocasio-Cortez said when asked directly if she would support Biden.

“If the president has a vision and that’s something we’re all willing to entertain and examine when the time comes… we should endorse when we get to it. We’ll take a look at it.”

“Right now we need to focus on winning a majority instead of a federal presidential election.”

Ocasio-Cortez is a vocal member of the Democratic party’s left wing, which has been pushing Biden to take executive actions to get past a congressional logjam in his agenda.

But there appears to be growing discomfort with the 79-year-old president across the array of Democratic ranks.

The New York Times reported on Saturday that “dozens of frustrated Democratic officials, members of Congress and voters” were doubtful Biden possessed the ability to turn around the party’s fortunes.

And New York magazine’s Intelligencer explored the issue of Biden’s longevity last month, noting that: “Many of the Democratic Party’s biggest donors – even as they pledge to back Biden’s reelection in earnest – have quietly started to poke around for alternatives in 2024.”

Biden is mired by the lowest approval ratings of his presidency and seemingly unable to solve a raft of problems facing the country from inflation to abortions rights and gun reform.

Despite Democrats having control of the White House and both chambers of Congress, he has also been unable to advance signature policy objectives such as the Build Back Better act and voting protections.

Adding to the discomfort is Biden’s age: he will turn 82 the day barely two weeks after he would be seeking re-election.

“The presidency is a monstrously taxing job and the stark reality is the president would be closer to 90 than 80 at the end of a second term, and that would be a major issue,” David Axelrod, former president Barack Obama’s chief strategist, told the New York Times.

Ocasio-Cortez did tell CNN that she thought Biden was “doing a very good job so far” and didn’t rule out eventually backing him “if the president chooses to run again”.

Traditionally, however, sitting first-term presidents have always enjoyed the unswerving loyalty and backing from their party, something Biden clearly does not have. The questioning is expected to intensify if, as polls suggest, Democrats take a hammering in November’s midterms and lose control of one, or both chambers of Congress.

“[Biden] should announce his intent not to seek re-election right after the midterms,” Steve Simeonidis, a Miami-based member of the Democratic national committee (DNC) told the Times.

“To say our country was on the right track would flagrantly depart from reality.”

Many of the Democrats interviewed by the newspaper, including elected officials, indicated the situation was not helped by a lack of clarity over a natural successor.

At a Detroit rally during his 2020 campaign, Biden said he viewed himself “as a bridge” to a younger generation of Democratic leaders, an indication that his objective was to run to get Donald Trump out of office, then prepare to hand over the baton.

But vice-president Kamala Harris, once seen as Biden’s heir apparent, has struggled to make a mark, despite attempting to seize the lead on Democrats’ opposition to the supreme court’s expected imminent ruling ending almost half a century of abortion rights.

Biden has indicated he intends to run again, telling his old boss Obama in April that he was preparing for 2024 with Harris on the ticket. Sources said he sees himself as the only candidate capable of keeping Trump out of the White House if the former president launches another campaign.

According to Intelligencer, Democrats are broadly split into two camps, those who see Biden’s troubles as familiar midterms woes facing most administrations, with fortunes set to improve as 2024 approaches; and those who consider that the unprecedented combination of circumstances, including Biden’s age, his strategy and uncertainty of succession, make a future path uncertain and unpredictable.

Jasmine Crockett, a Democratic Texas state representative, told the New York Times that many of her party’s problems at a national level, and by extension Biden’s problems too, come down to one thing: failing to stimulate voters by using their power.

“Democrats are like, ‘What the hell is going on?’” Crockett said.

“Our country is completely falling apart. And so I think we’re lacking in the excitement.”