A 21-year-old man escaped police custody Tuesday afternoon while being walked into Brooklyn Criminal Court for arraignment, police said.

The man fled on foot around 1 p.m. as officers were transferring him from a police vehicle into the building at 120 Schermerhorn St., according to police.

He was being transported from the 73rd Precinct stationhouse in Brownsville to central booking when he ran, authorities said.

Police did not immediately identify the man or say what he had been arrested for.

This is a developing story and may be updated.