According to Nepal police, more than 500 tourists are missing from 28 different countries - most of whom are foreign nationals.

The Nepal Tourism Board has broken down the missing by nationality. Its latest announcement on Thursday morning, external said there are 65 people from the US and 25 from Canada.

State media in China, which controls Tibet, reported three dead and at least 558 missing there. Among these are 260 foreign nationals, CCTV said. It is not clear if these figures overlap with Nepal's.

CCTV from Tibet showed a wall of water and mud hitting buildings at a border crossing.

The US State Department did not provide figures or additional details regarding the Americans affected for privacy reasons.

Canada's Prime Minister Mark Carney said his government was closely following the situation.

The prime minister said all Canadians in the region should sign up for Registration of Canadians Abroad, a free service that lets the federal government contact and assist citizens during an emergency in other countries.

Canada's foreign affairs office said 820 Canadians are registered as being in Nepal and five Canadians are registered as being in the Tibet Autonomous Region, China, citing the Registration of Canadians Abroad system.

The office emphasised that the numbers are only estimates as registration is voluntary and includes registrants that might not have made travel plans.

"The Department is aware of Canadians who have been affected by the floods," the Global Affairs Office said in a statement to the BBC.

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