NEW YORK (AP) — New York Mayor Michael Bloomberg is again calling on the presidential candidates to come up with a specific plan on gun control.

Bloomberg said Monday it is incumbent on President Barack Obama and GOP candidate Mitt Romney to address the issue "specifically — not in just broad terms."

Bloomberg spoke on MSNBC in the wake of the mass shooting in Aurora, Colo.

He asked how anyone can run for the highest office in the country and not have a plan.

He said some people feel it's insensitive to talk about gun control as the nation mourns Colorado's victims. But he asked: "If not now, when?"

Bloomberg heads up a coalition of American mayors who support tighter gun control. The group has lobbied for stronger enforcement of existing laws.