The former head of US intelligence blasted one of the officials who signed the letter casting doubt on Hunter Biden’s laptop — calling him a lying “phony” and igniting a Twitter war over the weekend.

The spat erupted Saturday when Richard Grenell, the former Trump-appointed acting director of national intelligence, reacted to a post from John Sipher, who retired from the CIA in 2014, about ethical behavior among public servants.

“Didn’t @john_sipher sign a letter 3 weeks before the 2020 elections saying don’t look at Hunter Biden’s laptop because it’s Russian disinformation?” Grenell tweeted Saturday. “Now he’s lecturing people about ethical behavior?! These people have no shame….”

The letter was signed by 51 former intelligence officials, including Sipher, and released after the New York Post revealed the existence of the laptop, which Biden left at a Delaware computer repair shop, in October 2020.

It contained a trove of emails about Biden’s business dealings in China and Ukraine that implicated his father, then-Vice President Joe Biden.

At the time the report was published, Biden was the Democratic presidential nominee.

The exchange between Sipher and Grenell appeared to be prompted by a tweet that ​called for Republicans — if they take control of Congress this year — to revoke the security clearance of all former intelligence community members who signed the Biden letter.

The heated back-and-forth bled into Sunday when Grenell admonished Sipher for signing the letter that wrongly discredited the laptop as Russian disinformation. Sipher was among the dozens of signatories who then refused to respond to The Post when asked whether they would apologize now that the New York Times confirmed the existence of the laptop. 

​”​You signed the letter and then refused to respond to th​e ​@nypos​t​. So stop the name calling and answer – is Hunter Biden’s laptop Russian disinformation?​” Grenell posted. ​

He followed up that post with another.

​”​While I was calling for sanctions on Putin’s pipeline,​ ​@john_sipher​ ​was saying Hunter Biden’s laptop was Russian disinformation. You lied. There wasn’t a single piece of intel that suggested it​,” Grenell said in the tweet, linking to a Post editorial seeking a response from Sipher and the others.

​Sipher responded to Grenell, saying “read the letter.”

​”​There are no lies there. The Russians clearly used the issue to damage our country but you and your ilk merely enabled and furthered Russian disinformation. Then again, you will support anything – even lies – to suck up to Trump​,” Sipher tweeted.

Grenell countered that he’s “obsessed” with identifying people who “manipulated intelligence for their partisan political gain.”

“*YOU* said Hunter’s laptop was Russian disinformation. You told the public not to take the laptop seriously. You pretended to have seen intel,” he said. “You didn’t even get a briefing!”

Sipher responded, “Ha.”

“Says the man who failed to say a word when his boss said he trusted Putin more than his own intelligence community,” Sipher said.​

Two minutes later, Grenell shot back. ​

“​Lol. He can run but he can’t hide​,” he said. “​He’s a phony. Who lied about intel.​”

A few minutes later, Grenell posted again and included an image of Sipher blocking his tweets. 

​”​lol. He signed the letter saying Hunter’s laptop was Russian disinformation​,” Grenell said.

Sipher, responding to an earlier tweet, warned Grenell that he would have to block him. ​​

“​Look who’s trying to use a non-issue to be relevant,” he tweeted. “Sad. He blocked me over two years ago when he was an official and couldn’t take criticism. I’m gonna have to block him now so he doesn’t misrepresent me to the nut jobs that follow him. Bye Dick. It was fun.”