More than 5,200 people are believed to have died in devastating floods across eastern Libya, a spokesman for the Ministry of Interior said Tuesday.
Another 10,000 people are believed to be missing, according to Tamer Ramadan, Libya envoy for the International Federation of Red Cross and Red Crescent Societies.
"The death toll is huge," Ramadan said during a press briefing on Tuesday.
In just the city of Derna, the worst hit area, at least 700 people have been confirmed dead from the unprecedented flooding. A quarter of Derna was wiped out after dams burst and the city was declared a disaster zone, with electricity and communication having been cut off.
Emergency workers uncovered more than 1,500 bodies in the wreckage of Derna on Tuesday, according to The Associated Press.
An additional 1,200 people were injured in the flooding in Derna, according to authorities.
The cities of Al Marj, Susah, Shahat and Al Bayda have also recorded several fatalities.
Rescue and relief efforts were underway on Tuesday to assist those affected by the flooding, according to Gen. Khalifa Haftar, head of the powerful Libyan military faction that controls the eastern part of the divided country.
"We issued immediate instructions to use all our capabilities, provide the needed support of all urgent medical equipment, operate medical convoys and to allocate shelters to those who lost their homes," Haftar said in a televised address on Tuesday. "We have directed the government to form a specialized committee to assess the damage, instantly begin the reconstruction of roads to facilitate transportation, restore the electricity and to take all immediate and needed measures in that regards."
President Joe Biden and the first lady are sending their "deepest condolences" to families in Libya who've lost loved ones in the devastating floods.
In a statement, Biden said the U.S. is "sending emergency funds to relief organizations and coordinating with the Libyan authorities and the U.N. to provide additional support."
Mediterranean storm Daniel is behind the widespread flooding in the North African nation as it swept away entire neighborhoods and destroyed homes in several coastal towns over the weekend.
Libya's National Center of Meteorology reported that more than 16 inches of rain fell in the city of Bayda within a 24-hour period to Sunday, according to the flood tracking website Floodlist.
Initial reports indicated that the storm damaged dozens of cities and villages in the area, according to Georgette Gagnon, the United Nations humanitarian coordinator for Libya.
"I am deeply saddened by the severe impact of [Storm] Daniel on the country and have tasked an emergency response team to prepare to support local authorities and partners in the region," Gagnon wrote in a post on social media on Monday. "I call on all local, national and international partners to provide urgent humanitarian assistance to those affected at this difficult time."
U.S. Special Envoy to Libya Ambassador Richard Norland announced Tuesday that the American embassy in Tripoli "has issued an official declaration of humanitarian need in response to the devastating floods in Libya."
"The declaration of humanitarian need will authorize initial funding that the United States will provide in support of relief efforts in Libya," Norland said in a statement. "We are coordinating with U.N. partners and Libyan authorities to assess how best to target official U.S. assistance. In addition, we have been contacted by many Libyan Americans anxious to make private contributions to relief efforts and we will work with Libyan authorities to direct those resources to where they are most needed."
Last week, the same storm system hammered the southeastern Mediterranean, killing at least 26 people in Greece, Turkey and Bulgaria, according to The Washington Post.
ABC News' Joe Simonetti and Justin Gomez contributed to this report.