The death toll from last week’s catastrophic flash floods along the Nepal-Tibet border has risen to at least 750, with thousands of people still missing as search-and-rescue operations continue, according to Nepali and Chinese authorities.

Nepal’s National Disaster Management Authority said Sunday that at least 734 bodies had been recovered across affected areas, while 2,498 people remained unaccounted for.

Across the border in China, state-run Xinhua News Agency reported at least 16 confirmed deaths, with another 546 people still missing.

Foreign nationals are among those unaccounted for. The U.S. State Department said at least 90 Americans remained missing as of Friday. Five U.S. citizens had been evacuated from the disaster zone, up from three a day earlier.

“There is no higher priority for us than the safety of American citizens,” the State Department said, adding that U.S. embassies in Nepal and China were working to assist Americans and support ongoing relief efforts.

Washington has also announced $3.6 million in emergency humanitarian assistance for Nepal. The package will include life-saving support and up to three months of emergency food assistance for as many as 10,000 households affected by the floods.

The disaster struck Nepal’s northern Rasuwa district near the Tibetan border at around 8:40 a.m. local time Wednesday. Powerful floodwaters surged along the Trishuli River, burying buildings under mud and debris while destroying bridges and damaging roads.

Dramatic footage from the region showed torrents of water and debris tearing through mountainous communities as residents scrambled for safety.

Analysis of verified video and satellite imagery indicated that the destructive surge traveled at least 62 miles downstream from the Nepal-Tibet border, leaving widespread devastation along its path.

With more than 3,000 people reported missing across Nepal and China, authorities fear the death toll could climb further as rescue teams continue searching remote and heavily damaged areas.