North Korean leader Kim Jong-un has expressed his "bitter sorrow" after dozens of Chinese tourists were killed when a bus they were travelling in plunged off a bridge.

Chinese officials and state media said 32 Chinese tourists and four North Koreans were killed in the crash south of Pyongyang on Sunday night.

Two other Chinese nationals were injured.

In a rare admission of negative news from North Korea's tightly controlled propaganda network, the KCNA news agency said Mr Kim met the Chinese ambassador in Pyongyang and later visited survivors in hospital.

The Rodong Sinmun newspaper, the mouthpiece of the ruling party, carried a front-page on Mr Kim's actions, including pictures of him in a doctor's white coat, holding the two survivors' hands as they lay in their hospital beds.

Although such a move might be unsurprising in other countries, it is an unusual portrayal of Mr Kim, who is usually shown presiding over formal meetings or visiting work or army units.

Mr Kim said that the crash brought "bitter sorrow to his heart" and he could not control his grief at the thought of the bereaved families who lost their relatives, KCNA reported. 

The North Korean leader said his people "take the tragic accident as their own misfortune", KCNA added.

Mr Kim's comments reflect the importance of China - and its tourists - to his country and economy.

Beijing is Pyongyang's sole major ally, providing an important economic and political buffer against international opprobrium.