Gov. Andrew Cuomo is back in New York today after a whirlwind trip to Afghanistan.

The governor received counterterrorism briefings and visited New York soldiers during his trip with three other governors.

Cuomo says the state is a top terror target. In light of last week's revelation during the U.N. General Assembly of a potential threat to New York City subways, Cuomo says he wants to understand why terrorism continues to grow.

In a conference call Sunday, Cuomo said much progress has been made in Afghanistan, but Islamic State extremists are now spreading a new "virulent strain of terrorist activity and culture." He said his goal is for New York to have "the most sophisticated homeland security system ever designed," but terrorist cells also have to be controlled at their source.

About 270 members of the New York National Guard and about 900 members of Fort Drum's 10th Mountain Division are stationed in Afghanistan.

Cuomo traveled with Department of Defense officials and governors Brian Sandoval of Nevada, Bill Haslam of Tennessee and Jay Nixon of Missouri.