NEW YORK - New York City stepped up its police force in major public locations on Monday in the wake of the death of Osama Bin Laden.

More policemen and police vehicles have been deployed at Times Square and in the financial district since Monday morning. "The extra security is a precaution against any possible terrorist retaliation for the death of Bin Laden," a policeman at Times Square told Xinhua.

The police presence was also increased in key subway hubs throughout the city. Emergency service vehicles were at subway locations, and helicopters were flying directed patrols over key sites.

"We have been in coordination with local, state and federal law enforcement partners and increased security at key locations across the MTA's transportation system and remained on high alert," a Metropolitan Transportation Authority (MTA) spokesperson told Xinhua.

New York Police Department also put out a directive to all officers to be alert for suspicious packages or any evidence that the city's transit system, infrastructure and iconic locations are being targeted.

New York City Mayor Michael Bloomberg said during a press conference at the World Trade Center on Monday that New York City Police Department has built the most sophisticated counter- terrorism operation of any police department in the world and will adjust their strategies and deploy their resources based on the latest information.

"As of now, there are no new immediate threats against our city. But there is no doubt we remain a top target, and the killing of Bin Laden will not change that. Nor will it distract us from a mission that remains our absolutely highest priority: defending our city and country against all those who use violence to attack freedom," said Bloomberg.

US President Barack Obama announced the death of al-Qaida leader Osama bin Laden who planned the 9/11 terrorist attacks Sunday night.