Opponents of California's governor have enough valid signatures to trigger a state-wide vote on his leadership.

California's secretary of state said that 1.6 million valid signatures had been verified, some 100,000 more than were needed.

Gavin Newsom, a first-term Democrat, was up for re-election in 2022, but the recall means he will now probably face a vote this autumn.

Among the opponents he may face are reality TV star Caitlyn Jenner.

Should the recall election go ahead, it would only be the second such vote in California, and the fourth nationwide, in US history.

Voters would be asked if they want Mr Newsom to stay or another candidate to take over.

In a tweet, Mr Newsom said the recall "threatens our values and seeks to undo the important progress we've made".

Ousting Mr Newsom may prove an uphill battle in the heavily Democratic state, where he was elected in 2018 with support from more than 60% of voters.

The last Republican governor of the state was actor Arnold Schwarzenegger, who was elected in 2003 following a celebrity-studded recall vote.

Ms Jenner, a former Olympic athlete and a transgender celebrity, will be hoping for a similar result when she contests the next election as a Republican in the state.

Why is Governor Newsom facing a recall vote?

A campaign to recall Mr Newsom was launched by a conservative political group called the California Patriot Coalition in February 2020. Opposed to Mr Newsom's policies, the group started collecting signatures for a recall vote in June 2020.

The recall campaign gathered pace over Mr Newsom's handling of the coronavirus pandemic in the state.

As infections started to fall, he came under criticism from business owners for still enforcing restrictions. That criticism intensified in November 2020, when Mr Newsom was caught dining at a fancy restaurant for his political advisor's birthday, despite urging residents to stay at home.

He apologised for failing to "preach and practise" Covid-19 rules he imposed.

The campaign to remove Mr Newsom has come into sharp focus in recent months as critics have expressed frustration at the state's Covid-19 vaccine rollout, among other matters.

The state has not yet formally approved the recall or set a date for an election. But unless a significant number of valid signatures are withdrawn within the next 30 days, the vote will take place.

Under California law, the number of signatures calling for a recall vote must equal 12% of the number of votes cast in the previous election for that office.

In 2003, Democratic Governor Gray Davis was subject to a recall election, which he lost to Mr Schwarzenegger.

What reaction has there been?

In his tweet, Mr Newsom said his achievements on fighting Covid-19, helping struggling families, protecting the environment, and passing gun-violence solutions were at stake.

His campaign echoed his views, framing the recall as a power grab by Republicans whose chance of winning the office is slim, given their modest support in the state.

"This recall attempt is a far-right partisan power grab and a waste of money," Mr Newsom's Stop the Republican Recall campaign said.

To Republicans, the recall was a cause for celebration.

"I am ready to lead this movement," Republican former San Diego mayor Kevin Faulconer said, shortly after the signature count was announced. "Together, we will turn the page on Gavin Newsom's failures."