A suspect in last weekend's failed car bomb attack on Times Square was taken into custody early today while trying to leave the country, a law enforcement official said.

The suspect, a Pakistani, was identified at midnight Monday at John F. Kennedy International Airport and was stopped, said the official, who spoke to The Associated Press early today on the condition of anonymity because of the sensitivity of the investigation.

The suspect was identified as Faisal Shahzad, according to The New York Times, which said he is from Connecticut. He is being held in New York.

Meanwhile, an FBI-led Joint Terrorism Task Force on Monday took over the investigation into the bombing attempt amid growing indications that authorities are focusing on a possible international connection, U.S. officials and law enforcement sources said.

Earlier Monday, authorities were closing in on a man who they said was a naturalized U.S. citizen from Pakistan, according to a senior Obama administration official. The man is believed to have used cash to purchase the Nissan Pathfinder that was set ablaze but failed to detonate Saturday night on a tourist-crowded block in Midtown Manhattan.

Investigators and agents also were scouring international phone records showing calls "between some of the people who might be associated with this and folks overseas," according to a U.S. official who has discussed the case with intelligence officers. Investigators uncovered evidence - a piece of paper, fingerprints or possibly both - that also indicates international ties, according to a federal official briefed on the investigation. The material points to "an individual who causes concern to (investigators) who has overseas connections, and they are looking for him," the official said.

An overseas angle does not necessarily mean that the incident was planned or financed by al-Qaida or another organized group, investigators said. "Think smaller," said one senior law enforcement official, who spoke on the condition of anonymity because the investigation is ongoing.

Even as investigators emphasized that the probe is in its early stages and little is definitively known, they pursued what Obama administration officials characterized as a flood of new leads, both foreign and domestic. The Pathfinder's registered owner, for example, told investigators that he sold it several weeks ago to a stranger, in a cash transaction through Craigslist.

On a day of fast-moving developments from Manhattan to Washington Monday, President Barack Obama was repeatedly briefed on what a senior administration official called "a very active investigation." Attorney General Eric Holder said in the morning that it was too early to designate the failed bombing as an attempted terrorist incident. By afternoon, White House spokesman Robert Gibbs was calling it just that.

"I would say that was intended to terrorize, and I would say that whomever did that would be categorized as a terrorist," Gibbs said, sharpening the administration's tone.

Differences also emerged over the significance of a surveillance video that caught a man in his 40s changing his shirt in an alley and looking over his shoulder near where the Pathfinder was parked. New York City police officials characterized the man as acting suspiciously, but multiple federal law enforcement officials said he may not be the focus of the investigation.

"It looks like he was just taking off his shirt because he was hot," said one law enforcement official. Investigators were seeking to find another person captured on video running north on Broadway away from the area where the smoking sport-utility vehicle caused an evacuation of Times Square on a crowded weekend night.

Police said the bomb would have created a fireball that likely would have killed or wounded many people, making it the most serious bombing attempt in the United States since the Christmas Day attack aboard a commercial flight bound for Detroit.

The growing evidence of terrorist connections in the Times Square case led the New York-based terrorism task force to become the lead agency in the investigation, which had been overseen by the New York Police Department, a senior U.S. law enforcement official said. That indicates that the failed bombing is being investigated as a terrorist incident with international connections, the official said.

FBI Supervisory Special Agent Richard Kolko of the New York field division said in a statement Monday night that the "FBI JTTF (Joint Terrorism Task Force) and NYPD are working this case jointly and have been since the beginning." The New York police force, known for its expertise in terrorism matters, is represented on the task force and will remain heavily involved in the probe, officials said.

In the rear of the SUV, police found a makeshift bomb made up of three tanks of propane similar to those used in backyard barbecues; two jugs of gasoline; dozens of M-88 firecrackers, which are legal for purchase in some states; and a metal gun case holding 100 pounds of fertilizer that police said was incapable of exploding.

Some officials cautioned that the international focus did not mean that other possibilities, such as domestic terrorism or an individual acting alone, were being ruled out. Nor did it mean, they said, that international ties automatically constituted a well-formed plot.

One federal law enforcement official, for example, said international communications don't necessarily "get you to an international plot, a multi-organizational plot."

"We're just not there," the official said.

The nature of the possible international connection also remained murky. The Pakistani Taliban had asserted responsibility for the attempted bombing in a video posted on YouTube, but New York police and federal investigators have said no evidence had surfaced linking the group to the bomb.

On Sunday night, a second video was posted by apparent representatives of the Taliban, showing the group's commander, Hakimullah Mehsud, promising to launch attacks in the United States.

Mehsud, who U.S. and Pakistani authorities initially believed was killed in a January drone strike, was recorded saying, "The time is very near when our fedayeen will attack the American states in their major cities ... in some days or a month's time."

The video is marked with the logo of the Pakistani Taliban's official media wing, Umar Studios, and appears to be credible, according to Evan F. Kohlmann, a terrorism consultant at Flashpoint Partners.