Image copyright AFP Image caption The bus crash killed 32 Chinese people and four North Koreans

A tour bus has crashed in North Korea, killing 36 people including 32 Chinese nationals, Chinese officials say.

The crash, which also killed four North Koreans, happened in North Hwanghae province on Sunday night.

Chinese state media footage showed the blue tour bus completely flipped over, with part of its body broken.

Experts estimate that Chinese tourists make up 80% of foreign tourists to North Korea - providing an important source of currency for Pyongyang.

China is also the secretive regime's main political ally and largest trading partner.

Earlier, Chinese state broadcaster CGTN tweeted that more than 30 Chinese nationals had been killed after the bus plunged off a bridge - however, the post was later deleted.

There are no official tourist numbers for North Korea, but it is estimated that about 100,000 foreigners visit the country each year.

Tourists are subjected to tight restrictions - most visitors must be escorted at all times outside their hotels by guides employed by the government.