The feds and New York state yesterday boosted their terror threat alert levels one notch to high-risk “orange” – and FBI agents launched a nationwide manhunt for a Pakistani in the United States who might have terror links.

“New York has definitely been mentioned” as a target in terror suspects’ talk, a police source told The Post.

Another law enforcement source said the specter of an attack has been raised by an increased amount of “phone activity” in recent days among suspected terrorists – similar to that which occurred before the 9/11 attacks.

Though New York state raised its alert level, the Big Apple itself saw no change because it’s been at the high stage of alert since 9/11.

The wanted man, Mohammed Sher Mohammad Khan, 36, who illegally slipped into the country on Sept. 10, 2001, factored into the feds’ decision to raise the alert level – but he wasn’t the primary reason, FBI officials said.

Federal officials said Khan, who has several aliases, might know of a terror operation. His picture was given out to cops throughout the country, but the FBI was careful not to call him a terror suspect.

The new national terror alert also was triggered by “specific intelligence” received and analyzed by counterterrorism officials.

The latest intelligence info “has been corroborated by multiple intelligence sources,” Attorney General John Ashcroft said at a news conference.

Officials said the attack could be chemical or biological.

“Al Qaeda leaders have emphasized planning for attacks on apartment buildings, hotels and other soft or lightly secured targets in the United States,” Ashcroft said.

Ashcroft said the timing is related to the Hajj, the annual Muslim pilgrimage to Mecca in Saudi Arabia, which ends Friday.

Counterterrorism officials say other factors in the heightened alert level are the upcoming 10th anniversary of the first World Trade Center bombing on Feb. 26 and the prospect of war with Iraq.

There also were reports that Osama bin Laden might issue a message to his followers soon.

“We’ve also alerted the medical and public health communities,” Ridge said.

Ridge advised families to make communication and transportation preparations in case there’s an emergency, but said the higher alert shouldn’t cause anyone to cancel events or change travel plans.

The only other time the national threat level was raised to orange was last Sept. 10, the day before the 9/11 anniversary, and amid chatter about possible al Qaeda attacks on Western targets in Southeast Asia.