SHANGHAI, Jul 6 -- INVESTIGATORS probing an explosion at a karaoke parlor in Northern China suspect that hundreds of kilograms of explosives hidden in the parlor caused the blast that left 25 dead and 33 injured.

The explosion, on Wednesday night in Benxi Manchu Autonomous County in Liaoning Province, leveled all buildings within 300-square meters of the parlor.

Investigators said the blast was so powerful that it could only have been possible with "almost a ton of explosives," The Beijing News reported today.

The report also put the death roll at 26 or 27, including pedestrians at the scene when the blast occurred. But the figure has not been officially confirmed.

Investigators said they found TNT detonators at the scene. The detonators were made at a local factory in June, the report said.

It also cited locals as saying that the karaoke bar's owner, Qu Hua, who was killed in the blast, also owned a coal mine in the county. Locals said he stored explosives in the basement of the karaoke bar, according to the report.

Qu was said to be well known for his wealth in the county, which is home to more than 400 coal mines and an explosives factory, the report said.

Qu's wife and the music bar's employees were detained for questioning, according to previous reports.

Police were still processing evidence to determine the cause of the blast.

A receptionist at the karaoke parlor, who was seriously injured in the accident, told the Beijing News that she saw lots of smoke coming from the men's washroom when someone shouted "Fire!"

"Seconds later, I heard a 'bang' and lost consciousness," said Gu Yuanyan, 25, now being treated at a local hospital. "I felt like I was thrown out by the huge explosion and fell onto the road outside."

Adding to Gu's misfortune and injuries, she was run over twice by a truck as the driver tried to leave the scene, the report said.

Most of the dead were said to be young people as all six karaoke rooms in the parlor were full when the blast occurred, the report said.

The two-story parlor, which also held a bathhouse, was destroyed in the blast. Several vehicles were buried underneath the debris.

The blast also caused a blackout in the area until early yesterday morning, which resulted in a delay of emergency treatment to those injured in the blast, according to the report.

Windows close to the parlor were shattered while roof tiles of some buildings were ripped off, the report said.

The explosion was the latest in a string of blasts, fires and accidents in shopping malls, cinemas and other public places across China despite repeated government efforts to improve safety. Many of the mishaps were blamed on lax safety procedures and negligence.