At least three American tourists were reported among a “preliminary” toll of 384 missing people following serious flash flooding in Nepal, according to a statement posted to X by the Nepal Tourism Board.

The flooding occurred in the northern Rasuwa district, along the border with Tibet, at around 8:30 a.m. local time on Wednesday, authorities said.

The preliminary toll of the missing included 291 foreign nationals and 93 Nepali nationals, the Tourism Board said in its statement.

The three Americans were listed as traveling with a Nepali company called Fishtail Tours and Travel. The agency confirmed to ABC News that three American nationals are among the missing tourists traveling with them.

Efforts to locate and rescue the missing tourists is ongoing, the company said, without providing any further information on their possible whereabouts or wellbeing. 

The Nepal Tourism Board said that local tourism and law enforcement authorities were “working to verify the whereabouts and safety status of tourists and travelers who were in or traveling through the affected areas.”

Also among the foreign nationals listed as missing in the Tourism Board’s preliminary count were Indian, Malaysian, British, South African, Dutch and Australian tourists.

Rescue operations for flood-affected people were ongoing via air transport as of Wednesday, the Nepali Army said in a post to X on Wednesday. The army urged people to adopt high vigilance and stay in safe places. 

The flood reportedly inflicted casualties on the Chinese side of the border, at the Gyirong border crossing, according to the Chinese state-run Xinhua News Agency.

President Xi Jinping, the agency reported, ordered search and rescue efforts for those reported missing.

This is a developing story. Please check back for updates.

ABC News’ Somayeh Malekian and Charlotte Gardiner contributed to this report.