A self-described Palestinian migrant accused of beating a Long Island Jewish man had been nabbed months earlier illegally crossing into the US and was almost immediately released.

Bechir Lehbeib, 26, of Mauritania sneaked across the southern border into Lukeville, Ariz., on July 20, 2023, with a group of more than 200 people, according to a House Judiciary Committee report on the migrant’s file exclusively obtained by The Post.

Lehbeib was released on his own recognizance two days later — after claiming he “feared” for his safety in his home country, the report said.

He made his way to New York, where in February, he allegedly stole a pro-Israel flag from a porch in Hewlett in Nassau County — before attacking the homeowner who tried to stop him.

The victim, Aleksandr Binyaminov, told The Post that one of his wife’s relatives was killed in the Oct. 7 Hamas terror attacks on Israel.

“I told him, ‘Give me the flags,’ and he just started fighting with me and punching me in my face,” Binyaminov recalled at the time.

“He basically got me in a choke position, threw me on the floor and headbutted me. He was saying, ‘I’m from Palestine.’ “

When Lehbeib was arrested, he allegedly told cops: “If I see the flag of the people that killed my people, we will have a problem.”

The accused migrant was hit with hate-crime charges of second-degree assault and robbery and criminal mischief and was detained on a $50,000 bond.

“This is happening because of open borders, and before letting people in, we need to see their backgrounds. We need to protect our country, our citizens, our taxpayers,” Binyaminov said at the time.

Authorities in Nassau County expressed outrage over the situation, too.

“Nassau County is not a sanctuary county,” said County Executive Bruce Blakeman, referring to the term for municipalities that limit or ban local law enforcement from reporting people’s immigration status to the feds.

Blakeman was outraged over the kind of alleged lax border vetting that allowed someone such as Lehbeib to roam free.

“These aren’t people kissing the ground when they come here. They’re spitting on our flag,” he said.

“It’s an invasion. It’s a disgrace.”

The House Judiciary Committee has released a series of reports this year highlighting crimes allegedly committed by migrants in major cities such as New York and Chicago.

Criminals are released into the US after entering illegally because of subpar “vetting” that is akin to referencing them “against a blank sheet of paper,” according to testimony former Border Patrol chief Rodney Scott made before a committee panel last year.