BROOKLYN — A man was fatally struck by a train at the Union Street R train station Wednesday afternoon, officials said.

The victim, who was believed to be in his mid to late 30s, was hit by a southbound R train at Union Street and Fourth Avenue in Park Slope at about 3:15 p.m., FDNY and MTA officials said.

There was no immediate information on how the man ended up getting struck, but there was no criminality suspected, according to the NYPD.

Southbound service was disrupted while police investigated, but resumed at about 5:57 p.m., according to the MTA.

But northbound trains were running with delays because of a signal problem at 25th Street, the agency's website posted at 6:02 p.m..

Riders can check the MTA's site for updates.