The 12 victims of a deadly traffic accident in Weihai, Shandong province, on Tuesday have all been identified, the local government said on Wednesday.

Eleven kindergarten students and the driver were killed when the bus with 13 people on board, including the children's teacher, rear-ended another vehicle in a tunnel around 9 am on Tuesday and burst into flames, said Ye Liyun, a deputy mayor of Weihai.

Five of the children, aged 3 to 6, were from the Republic of Korea and six were Chinese nationals. They were pupils at an international kindergarten in Weihai.

The identities of the driver and the children were confirmed through DNA tests on Tuesday, he said.

The teacher, who sustained serious injuries and was sent to Weihai City Hospital for treatment, is now conscious and appears stable, Ye said.

The Foreign Ministry said on Wednesday that the Chinese leadership was greatly concerned about the accident and issued instructions for dealing with the aftermath.

"We are in communication with the Republic of Korea through diplomatic channels" and will help with any issues that need to be resolved, a written statement on the ministry's website said.

Members of the ministry's staff have been assigned to provide comfort and assistance to the families of the victims, the statement said.

The Ministry of Public Security has also sent an expert team to Weihai to guide the investigation.

The Weihai city government has set up 13 teams for relief work, and Korean language interpreters have been assigned.

The children were from a kindergarten under the Weihai Zhongshi International School, which was set up in 2006 mainly to accommodate children of ROK businesspeople in Weihai.

"Due to the tragic loss in our community ... the school will remain closed for the remainder of the week and reopen on May 15," Tobin Holden, the principal, said in a notice published on the school's website.

Weihai, a port city on the eastern coast of Shandong across the Yellow Sea from the Korean Peninsula, has maintained close business relationships with the ROK. Large companies from the ROK, including Heavy Industries Co and Samsung Electronics, have facilities in the city.