BEIJING — Two men rammed a truck into a clutch of jogging policemen and tossed explosives, killing 16 officers today, state media said, in an attack in a restive province of western China just days before the Beijing Olympics, the state-run Xinhua News Agency reported.

Though it happened on the far side of the country — near the Afghan-Pakistan border — the attack came as security forces were on alert for protests or any disruptions during the Games, which open Friday. It was among the deadliest and most brazen attacks in years in Xinjiang province, site of a sporadically violent rebellion by local Muslims against Chinese rule.

About 20 people upset at having been evicted from their homes staged a brief demonstration near Tiananmen Square, Beijing's heavily guarded political center. Uniformed police quickly surrounded the group until members of a neighborhood committee came and pulled the protesters away, scuffling with some.

In the Xinjiang attack, the two men drove a dump truck into the group of border patrol police officers as they passed the Yiquan Hotel during a routine 8 a.m. jog in the city of Kashgar, the Xinhua News Agency reported.

After the truck hit an electrical pole, the pair jumped out, ignited homemade explosives and "also hacked the policemen with knives," Xinhua said.

Fourteen died on the spot and two others en route to a hospital, and at least 16 officers were wounded, Xinhua said.

Police arrested the two attackers, one of whom was injured in the leg, the report said.

Authorities closed off streets, sealed the Nationalities Hospital, down the street from the explosion, and ordered people to stay inside, said a man answering phones at the hospital duty office.

Local government officials declined to comment today. An officer in the district police department said an investigation was launched.