A high-speed passenger train has slammed into a group of workers conducting track maintenance in eastern China, killing 18 and injuring nine, the national work safety watchdog said.

The accident happened on Wednesday night along tracks near the city of Anqiu in Shandong province, the State Administration of Work Safety said in a notice on its Web site.

The cause of the accident was not given. A spokesman for the firm employing the workers, the China Railway 16th Group, blamed bad, snowy weather for the slow reporting of the accident.

However, the official Xinhua News Agency said the workers had arrived at the site ahead of the hour at which trains were supposed to approach with caution.

According to Xinhua, track work was scheduled to start at 10 p.m. and trains were to slow their speed to 28 mph starting from 9 p.m. But the workers entered the work area at 8:40 p.m. and soon afterward were hit by the speeding train, traveling in the night at more than 120 kilometers (75 miles) per hour, the news agency said.

Xinhua said the injured were in a hospital in stable condition. The high-speed passenger train was traveling from Beijing to the port city of Qingdao in Shandong.