Authorities in Jersey City, N.J. already on edge following the ambush-killing of a rookie police officer over the weekend, are on high alert after the street gang The Bloods purportedly vowed to kill even more Jersey City cops after last week’s slaying of Officer Melvin Santiago.

A senior law enforcement official told the New York Post that the infamous gang has threatened to “kill a Jersey City cop and not stop until the National Guard is called out.”

An internal Port Authority advisory obtained by The Post warned that some Bloods gang members may be traveling from out of state to target officers in New Jersey.

“New Jersey State Police has received credible information from the Jersey City Police Department about specific threats toward Jersey City police officers and law enforcement,” the advisory read. “The United Blood Nation may take retaliatory action against police officers.”

Meanwhile, officers from Jersey City and surrounding towns showed up Tuesday afternoon to relocate memorial items from the site where Santiago was fatally shot to death near the West District precinct, where he had been assigned.

Officers, including some who had canceled vacations or come in on days off in a show of support, paid their respects in front of the memorial, set up on a table with a placard that read "End of Watch 7-13-14" under Santiago's name.

West District Commander Capt. Michael J. Kelly said on Tuesday an officer shot a man who attacked him and his partner with a sharpened fence post. Kelly said the shooting did not indicate that officers were in a heightened state of alert in the wake of Santiago's killing.

"Our officers are always in a high-alert state. That's part of our profession. It's a dangerous profession," he said.

The man, whose name was not released, was taken to a hospital and was expected to undergo surgery for non-life-threatening injuries, the prosecutor's office said. The police officers were also being treated.

Kelly said condolences have been pouring in from departments across the region. He described Santiago as a quiet, serious young man who had dreamed of being a police officer since childhood and who had just started to hit his stride after less than a year on the job.

According to a preliminary investigation of Tuesday's shooting, two officers with the emergency services unit saw the 25-year-old man at about 2:30 a.m. and ordered him to drop the fence post, the Hudson County Prosecutor's Office said in a statement.

Authorities said the man threw the post through a passenger-side window of the emergency services truck, hitting an officer in the head. The man then reached through the window and grabbed the officer's rifle, authorities said. The two struggled for the rifle, which discharged through the vehicle's door and struck the man, officials said.

The officers exited the vehicle and ordered the man to the ground. One officer opened fire, striking the man, after authorities said the man refused to show his hands and hid a hand in his waistband.

Santiago was ambushed Sunday as he responded to an armed robbery call at an all-night Walgreen's, authorities said. Other officers returned fire, killing Lawrence Campbell.

Angelique Campbell, Campbell's widow, said she doesn't plan to restore a memorial to him that went up in their neighborhood but was taken down by Tuesday morning.

She had told News 12 New Jersey on Sunday that she was sorry for Santiago's family but that her husband should have killed more officers if they were planning to kill him. She later apologized for the comments.

"Both families are hurt. Let this cop be laid to rest peacefully. Let Lawrence be put to rest peacefully. That's it," Angelique Campbell told The Associated Press on Tuesday. "There's no back-and-forth. I don't want to argue with no cops, I don't want to fight with no cops. I just want to put him in the ground, he's gone, that's it."

Based on reporting by The Associated Press.

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