Beijing has pledged to improve the mining industry

Lan Chengzhang was set upon by a "group of mining thugs" near a mine in Huiyuan county, Shanxi province, the Beijing-based China Trade News said.

Another newspaper quoted a journalist with Mr Lan as saying the attack had been ordered by a local coal mine boss.

China's coal mines are among the most dangerous in the world.

More than 5,000 deaths are reported every year, many of them in illegal or unregulated mines.

Lan Chengzhang had only just started at the newspaper and was still in his trial period when he was killed, the China Trade News' head of news Wang Jianfeng said.

Mr Wang said the newspaper had sent a team to investigate the killing and had made official complaints to the local police and government.

"We will do everything we can to protect the rights of journalists," he told the AFP news agency.

Search for profits

Mr Lan had been investigating the story with a fellow journalist, another newspaper, the Southern Daily, reported.

The surviving journalist accused an unnamed boss of a coal mine in Huiyuan of orchestrating the beating.

He said he had been detained in the boss's office while the attack was carried out, the newspaper said.

Beijing has pledged to take action to improve the mining industry, which is blighted by poor safety procedures and a lack of proper equipment.

Mine owners are accused of frequently ignoring government regulations in search of greater profits.