After Osama bin Laden's death was announced by the president late last night, locals are reacting with relief and happiness that the mastermind behind the 9/11 attacks has been killed.

Others gathered in Times Square and at Ground Zero as soon as President Obama's speech began, with the jubilant crowds waving American flags and singing the National Anthem in celebration.

While everyone agreed that bin Laden's death was very welcome, there was still concern that a retaliation attack on Americans could occur. Security has been increased at U.S. embassies around the world and in New York City.

At the 9/11 Memorial in Haverstraw, a few visitors took the time to reflect on the momentous events of the past day while police officials promised to remain vigilant.

"We're out there all the time with our counterterrorism efforts. Certainly the Tappan Zee Bridge and critical infrastructure like that," says Chief Robert Van Cura, of the South Nyack and Grandview Police Department.

Osama bin Laden killed during U.S. operation in Pakistan

VIDEO: President Obama announces Osama bin Laden's death

Text of President Barack Obama's announcement