Heightened security concerns continue in the U.S. after the deadly attack in Brussels.

FOX's Gurnal Scoitt in New York:

In Times Square the presence of New York's finest cautiously armed among natives and tourists symbolizes the gravity of the deadly attack in Belgium.

NYPD Commissioner Bill Bratton says Metro transit is being closely watched:

(Bratton) "Additionally we will be providing extra coverage to Belgian and French interests here in the city."

Bratton has often said that terrorists often pursue successful attacks on New York City post 9/11, but right now no credible intelligence exists that require New York to be on its highest alert.

In New York, Gurnal Scott, FOX News.