Two Chinese coal mine officials have been arrested for alleged dereliction of duty after an explosion that killed at least 164 miners.
Rescuers say there is little chance of finding more survivors
About seven others are still said to be missing, amid conflicting reports about how many people were in the mine.
The coal dust explosion at the Dongfeng mine in Heilongjiang province destroyed the mine's ventilation system.
Accidents remain widespread in China's mines, despite a much-publicised government safety campaign.
Police arrested the head of the mine, Ma Jinguang, and local Communist Party secretary Chen Zhiqiang, the China Daily newspaper reported.
Ma Jinguang had been declared a role model in mine management 10 days before the accident, the paper added.
Before the arrests were made known, the national work safety watchdog publicly rebuked the mine's management for failing to act on warning signs in the run-up to the explosion.
Police and mine investigators have reportedly taken away documents, minutes of meetings and account records from the offices of the mine, which is run by Heilongjiang Longmei Mining Group, a state-owned conglomerate.
Some 72 miners have so far been rescued alive since Sunday's blast, 38 of whom are being treated in hospital, Xinhua news agency says.
Officials were quoted as saying the chances of finding more survivors were very low because of the levels of toxic gas in the mine.
China has the worst mine safety record in the world.
Chinese officials say some 6,000 miners died last year, but non-government groups say the true figure is far higher.
This year, 3,000 deaths have been reported in the country's mines.
The China Daily newspaper said that following the government drive to increase safety, 9,000 illegal coal mines have been closed since September and almost 13,000 dangerous ones suspended.
But the paper admitted that the central government's attempts to improve safety were being compromised by local authorities ignoring unsafe mines because they made money.
"We suggest that an accountability mechanism be established immediately for provincial and county inspectors who conduct safety checks at suspended coal mines," the paper said.
The paper called for inspectors to be held "directly responsible for any accidents that take place due to poor safety".