Rush-hour commuters faced significant subway delays Thursday night after a manhole caught fire near the West 4th Street station — and some lines could still be affected Friday morning, MTA officials warned.

The fire, which started at 6:30 p.m., damaged signal cables on the A, B, C, D, E, F, M and R lines.

A, C and E trains were suspended between Canal Street and Columbus Circle, while B, D and F trains were running express from Canal Street to 59th Street, officials said.

The MTA was still investigating the blaze early Friday.