Signal issues briefly disrupted Amtrak and New Jersey Transit service into and out of the city Friday morning, the transit agency said.

At around 11 a.m., Amtrak said all trains running between New York-Penn Station and Philadelphia were being held until further notice due to an "ongoing communication issue with signals and switches." The signal issues were resolved just before noon.

The issues also caused disruptions on NJ Transit, which suspended service on the Northeast Corridor, Raritan Valley Line and North Jersey Coast Line.

Service resumed around noon, but both Amtrak and NJ Transit warned commuters to expect residual delays.