A cop in Midtown arrested a man early Sunday for trying to grab his gun from its holster in Penn Station, police sources said.

Robert Pelletier, 30, was walking behind the uniformed officer about 1:25 a.m. in the train station when the officer felt pressure on the right side of his gun belt, the sources said.

When the cop turned around, Pelletier was trying to take the Glock 19 out of its holster, the sources said.

The gun was never removed and there were no injuries.

Pelletier, of Greenfield, Mass., was charged with robbery in the third degree and criminal possession of a weapon.