In the wake of terrorism that is rattling nerves across the world, Mayor Bill de Blasio says New York City and the NYPD are prepared. The mayor on Monday looked over a counter terror training exercise and also repudiated — using perhaps his sharpest words yet — what he calls the counterproductive divisiveness of Republican presidential candidates.

It was a planning session for police with added urgency. Held just days after fatal attacks in Belgium. Security is on alert in New York City, for what could again happen here.

"In the likelihood that there will be an attack, and there will be at some point and time in our lives, that's the reality," said NYPD Police Commissioner Bill Bratton.

It's a reality that, before Brussels last week, hit Paris last year.

Officials in New York say they simulated four simultaneous attacks.

"On a major concert venue on the financial sector on another large public gathering place," said NYPD Deputy Commissioner John Miller.

It involved active shooters, a hostage situation, suicide bombers and multiple explosions.

The exercise also is useful to ensure lower profile parts of the city aren't less unprepared.

"We are hoping it won't be here," Commissioner Bratton said. "We are working very hard to keep it from happening here. But despite that hope despite that premise we need to be prepared."

And Mayor de Blasio says the city is well trained. Not only in its police department, but also in cooperation among citizens — which he says Republican candidates would undermine with counterproductive platforms targeting Muslims.

"Here are two men running for president of United States literally playing into ISIS' hands as is if they're  working from an ISIS script," de Blasio said. "Setting up an atmosphere of segregation and negativity."

Both Cruz and Trump have defended their proposals.

The Mayor's presence is more than reassuring. Officials say the entire exercise is also about preventing. It is a message to would be terrorists not to attempt a strike here.