A government probe into last month's deadly high-speed train crash is "proceeding in an orderly fashion," said a spokesman from China's work safety supervisory body.

Photo shows the crashed bullet trains in Wenzhou City of east China's Zhejiang Province. D301 train from Beijing to Fuzhou rear-ended the D3115 train at 8:50 p.m. The first four coaches of D301 and the 15th and 16th coaches of D3115 went off the line.

The accident was not caused by natural forces, but was an "extremely severe" accident related to the management of railway transportation, said Huang Yi, a spokesman from the State Administration of Work Safety (SAWS) during an online chat session hosted by people.com.cn, the online arm of the People's Daily newspaper.

On July 23, two high-speed trains crashed in Wenzhou city in East China's Zhejiang province. Previous media reports said authorities blamed the accident on lightning that hit the signal system and knocked the system vital for safety out of service.

Huang said that the railway authorities had also pointed out loopholes and deficiencies in safety management, which had emerged in the accident.

The State Council, or China's Cabinet, set up an investigation team shortly after the accident occurred, with Luo Lin, director of the Sate Administration of Work Safety, being appointed as leader of the team.

Investigation results are expected to be made public around mid-September, according to the SAWS.

Huang denied widespread rumors that death tolls for major accidents have been limited to 35 before being publicized, while the rest of the deceased have only been reported as missing.

"As far as I know, there are no such limits," he said. The rumor has been spreading through Internet chatrooms and microblogging sites since the train collision occurred.

According to Huang, the Chinese government usually defines accidents that cause more than 30 deaths as "extremely severe accidents," while those that claim 10 to 29 deaths are defined as "major accidents." Economic losses are also used to classify accidents, he said.

Different types of accidents are handled in different ways, he said.

Accident victims are considered missing until their remains are discovered, he added.

(Xinhua contributed to this story.)