Heavy rain lashed New York and New Jersey on Monday night, triggering flash floods that shut down subway lines, stranded vehicles and prompted a state of emergency across parts of the US Northeast.

A flash flood warning was issued for all five boroughs of New York City, while watches and warnings were also in place across surrounding areas including Baltimore, Newark, New Jersey, and Arlington, Virginia.

Some 50 million Americans across the Northeast were under flood watches.

New Jersey Governor Phil Murphy declared a state of emergency late on Monday “due to flash flooding and high levels of rainfall in parts of the state”.

He urged residents to “stay indoors and avoid unnecessary travel”, adding “stay safe, New Jersey”, in a post on X.

Videos posted online showed floodwaters rushing through streets. One clip captured cars submerged in New Jersey as alarms blared in the background.