At least 41 people have died in four northeastern states in the US as flash flooding caused by torrential rains from Hurricane Ida wreaked havoc overnight into Thursday, officials said.
Several people are said to have died in their basements during the "historic" weather catastrophe that officials blamed on climate change.
"We're all in this together. The nation is ready to help," said President Joe Biden, ahead of a trip Friday to the southern state of Louisiana, where Ida earlier caused massive destruction and left more than a million homes without power.
Unprecedented flood warning in New York
The remnants of Hurricane Ida unleashed record rainfall triggering the first-ever flood emergency warning for New York city.
Several roads turned into river-like torrents while New York subway lines were submerged.
The toll included four people who died at a public housing complex in Elizabeth that was flooded by 2.4 meters of water.
New York City reported 12 deaths, including 11 people who could not escape their basements.
Those who perished ranged from the ages of 2 to 86.
"We're enduring an historic weather event tonight with record-breaking rain across the city, brutal flooding and dangerous conditions on our roads," New York Mayor Bill de Blasio said late on Wednesday.
Lawmaker Alexandria Ocasio-Cortez said that people living in "off-the-books basement dwellings that don't meet the safety codes necessary to save lives" were the most vulnerable during the flash floods.
"These are working class, immigrant, and low-income people & families," she said.
State emergencies were declared in New York and New Jersey as the National Weather Service (NWS) urged residents to move to higher ground.
"You do not know how deep the water is and it is too dangerous," the New York branch of the NWS said.