BEIJING -- North Korean leader Kim Jong Un has offered his deep apologies to China after a bus crash in his country killed 32 Chinese tourists, state media said on Thursday.

China is North Korea’s most important economic and diplomatic backer, despite Beijing’s anger at Pyongyang’s repeated nuclear and missile tests and support for strong United Nations sanctions against North Korea.

The tourists and four North Koreans were killed when a bus crashed off a bridge in North Korea late on Sunday, leaving two Chinese nationals in critical condition.

On Thursday, Chinese state television broadcast images of Kim seeing off the bodies as they were loaded onto a train for the journey home.

The North Korean people were “overcome with sorrow,” Kim told President Xi Jinping and other Chinese leaders.

“It is, indeed, very sad that the close Chinese friends, who had come here with the feelings of friendship with our people, met with an unexpected accident on our land,” read his message, carried by the official KCNA news agency.

North Korean leader Kim Jong Un visits the Chinese embassy in Pyongyang following a bus accident involving Chinese tourists in North Hwanghae province, in this undated photo released on April 24, 2018 by North Korea's Korean Central News Agency (KCNA). KCNA/via Reuters

“We make a deep apology to the Chinese comrades for the pain which cannot be alleviated with any word, consolation and compensation.”

North Korea would make every possible effort to assuage the grief, it added.

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

Tourists from China are about four-fifths of all foreign visitors to North Korea, says South Korean think-tank the Korea Maritime Institute, which estimates tourism generates revenue of about $44 million each year for the country.

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

China has welcomed moves by Kim to ease tension over the North’s arms programs, including his summit this week with South Korean President Moon Jae-in.