Mayor Michael Bloomberg (search) and his police chief insisted Friday they did the right thing by going public with a terrorist threat to bomb the New York subway, brushing aside suggestions from Washington that they overreacted to information of dubious credibility.
While the mayor and federal officials weighed the threat's severity, the investigation into the alleged plot advanced as a third suspect was arrested and authorities looked into whether a fourth person took part in the scheme.
A law enforcement official in New York, speaking on condition of anonymity, said the tightening of security was prompted by an informant's report of a plot to attack the subway system with bombs hidden in bags and possibly baby strollers.
"If I'm going to make a mistake, you can rest assured it is on the side of being cautious," Bloomberg said.
The dispute came as thousands of extra police officers poured into the city's subway system, pulling commuters out of rush-hour crowds and rifling through their bags or briefcases in a crackdown that was announced late Thursday afternoon and continued on Friday.
The city's announcement of the alleged plot — and the warning to New Yorkers to keep their eyes open for anything suspicious — led to jostling between city officials and homeland security officials in Washington, who downplayed the threat.
Homeland Security (search) spokesman Brian Doyle said Friday: "The specified intelligence was checked out through the intelligence agencies. They looked at all the information and couldn't put a credible factor on it."
But Bloomberg and Police Commissioner Ray Kelly (search) vigorously defended their decision to go public.
"We did exactly the right thing," Kelly said.
The mayor's chief spokesman said the city had been working closely with the FBI and characterized the disagreement as a dispute within the federal government.
"When different federal agencies have different interpretations of the intelligence, the mayor doesn't have the luxury of knowing which one is right," Ed Skyler said. "He has to make a decision that provides the maximum level of protection to the people of New York."
A Department of Homeland Security memo obtained by The Associated Press said the attack was reportedly scheduled to take place Oct. 9, with terrorists using timed or remote-controlled explosives hidden in briefcases, suitcases or in or under strollers.
The memo said the department had received information indicating the attack might be carried out by "a team of terrorist operatives, some of whom may travel or who may be in the New York City area."
The memo, issued Wednesday to state and local officials, said that homeland security and FBI agents doubted the credibility of the information, but it provided four pages of advice about averting a possible attack, including tips on inspecting baby carriages with bomb-sniffing dogs.
In Iraq, meanwhile, authorities seized a third suspect Friday and investigated whether a fourth man had traveled to New York as part of the plot, according to the law enforcement official.
The official said the man's trip to New York was described by an informant who had spent time in Afghanistan and proved reliable in past investigations. But the official added that authorities had not confirmed whether the fourth man even exists.
Bloomberg called it the most specific terrorist threat that New York officials had received to date and said it was essential to err on the side of caution when protecting the city of 8 million.
Bloomberg took office months after the Sept. 11 attacks and is seeking another four-year term in next month's election.
Rep. Peter King, R-N.Y., said it was wrong for federal homeland security officials to try to discount the security concerns of New York officials.
"That sends a mixed message which confuses the people, and besides that, they're wrong," he said. "Even if there was some doubt as to what the right thing to do is, you shouldn't be having public disputes over that."
President Bush (search), asked if he thought New York officials had overreacted, said: "I think they took the information we gave and made the judgments they thought were necessary."
The dispute played out as new details emerged about the alleged plotters.
U.S. forces in Iraq arrested two suspected plotters who had been under close surveillance until Thursday morning, the law enforcement official in New York said. A third suspect escaped but was captured Friday.
Those arrested had received explosives training in Afghanistan (search), the law enforcement official said. They had planned to travel through Syria to New York, then meet with operatives to carry out the bombings, according to the official. The official said that the threat was "specific to place," and that the window for the attack ran from Friday through at least the weekend.
A federal official said one of the suspects arrested in Iraq apparently told interrogators that more than a dozen people were involved in the plot, and that they were of various nationalities, including Afghans, Syrians and Iraqis. The official spoke on condition of anonymity because the investigation is continuing.
In Baghdad, spokesmen for the U.S. military and the U.S. Embassy (search) declined to comment on the arrest.
Homeland Security's Doyle said the government has no information that the fourth person possibly connected to the plot "is either here or even exists."
On the streets of New York, more officers were visible in several parts of the city.
"Hopefully, God's with me and I'll be OK," Vinnie Stella said as he entered the subway at Penn Station (search).
Rob Johnson, 30, said he was not worried: "The cops have it under control."
Rob McGoey, who grew up in New York and now lives in Nebraska, said Friday was the first time he had been stopped and searched. "It was never this way when I lived here," he said. "It's scary, actually."
Authorities briefly closed part of Penn Station after a discarded soda bottle filled with a green liquid was found during morning rush hour. The police commissioner said it was a type of drain-cleaner and not a threat.
An estimated 4.5 million passengers ride the New York subway each day. The system has more than 468 stations. In July, the city began random subway searches in the wake of the train bombings in London.