ROME - A speeding car plowed head-on into a group of cyclists in southern Italy yesterday morning, killing eight of them, officials said. The driver had been smoking marijuana, police said.

Bent, mangled bikes were strewn about the scene, and the sheet-draped corpses dotted the two-lane road near Lamezia Terme, in the Calabrian "toe" of boot-shaped Italy, where the accident occurred.

In addition to the eight cyclists killed, four people were injured: two cyclists and the driver, and a young boy in the car with him, said Maria Dolores Rucci, commander of the road police in nearby Catanzaro.

The ANSA news agency said that the driver, who was only slightly injured, was placed under arrest on charges of multiple homicide. A police spokesman, who declined to give his name, said that the man, a Moroccan national, had tested positive for marijuana.

A preliminary investigation showed that the speeding car ran headfirst into the group of 10 cyclists who were riding in the opposite direction on state road 18, according to Italy's highway authority.

ANSA said that the driver was trying to pass another car when he hit the group. Visibility was good at the time, reports said.

The road, closed by authorities for most of the day, reopened yesterday evening.

It is common in Italy to see groups of amateur cyclists taking to small state roads on weekends; ANSA said that the group that was hit yesterday was affiliated with a local Lamezia Terme gym.

As a result of the crash, Italian cycling officials complained about safety problems for cyclists who have to share roads with cars.

The head of Italy's cycling federation, Renato Di Rocco, denounced the violent "massacre" of the cyclists and sent his condolences to their families.

The mayor of Lamezia Terme, Gianni Speranza, announced a day of mourning for the dead, ANSA said.