Chinese tourists have been involved in a major bus accident in North Korea that caused a large number of casualties, China’s state media and the government said on Monday, without giving details of how many died or were injured, wrote reuters.

Chinese visitors account for about 80 percent of all foreign tourists to North Korea, says a South Korean think-tank, the Korea Maritime Institute, which estimates that tourism generates about $44 million each year in revenue for the isolated country.

Chinese diplomats have rushed to the scene of Sunday’s accident in North Hwanghae province, the foreign ministry said.

In a Twitter message earlier on Monday, Chinese state television’s English-language channel said a tour bus had fallen off a bridge, killing more than 30 people, but later deleted the message.

State television’s main Chinese-language news channel later showed images of a crashed blue bus with its wheels in the air, in footage taken in pouring rain in the dark.

It showed at least one person being treated in hospital, but also gave no details of casualties.

In a separate statement, China’s health ministry said it was sending a team of medical experts along with equipment and drugs to North Korea to help treat survivors.

The North Hwanghae province that borders South Korea is home to Kaesong, an ancient Korean capital thronged by tourists.

North Korea is a popular, if offbeat, tourist destination for Chinese, especially those from the country’s northeast.

China said more than 237,000 Chinese visited in 2012, but stopped publishing the figures in 2013.