SAPPORO (Kyodo) Relatives and friends of 20 people killed after a massive rock fall in a highway tunnel in 1996 in Hokkaido gathered near the disaster site Sunday to hold a 10th anniversary memorial ceremony.

Some 20 relatives and friends of the victims, including Tetsuo Homma, 55, who lost his 17-year-old son, Atsushi, in the accident, offered incense and prayers at an alter set up for the joint Buddhist service in the town of Furubira.

"I still remember watching the rescue operation in the freezing cold at the accident site 10 years ago," said Homma, who heads an association of the victims' families.

At around 8:10 a.m. on Feb. 10, 1996, a huge shard of rock weighing about 21,000 tons smashed through the Toyohama Tunnel near Yoichi, western Hokkaido, crushing a bus and a car and killing 20 people.

Hokkaido police turned over to prosecutors a case against two government officials in charge of the tunnel, on suspicion of professional negligence resulting in death and injury.

But the Sapporo District Public Prosecutor's Office dropped the case in March 2000, saying it was difficult for the officials to foresee the fatal rock fall.

Meanwhile, in a March 2001 ruling, the Sapporo District Court ordered the government to pay roughly 450 million yen in compensation to the families of seven of the victims.