The Associated Press

VLADIKAVKAZ, Russia (AP) - Hundreds of protesters in Chechnya's third-largest city on Tuesday demanded Russian forces end a security sweep that has kept residents trapped in the town for two days.

Argun has been under Russian fire since last Thursday as federal forces try to flush out rebels who the Russians say took refuge there.

Three Russian soldiers were killed in a battle Monday and six wounded, an official in Chechnya's Moscow-appointed administration said Tuesday. Seven rebels were killed in the fighting, in which Russian troops fired rockets at a building where rebels were hiding, the official said on condition of anonymity.

Argun has been cordoned off since Sunday. About 100 suspected rebels have been detained, the official said. Only vehicles carrying troops are allowed in and out of the town, according to the Interfax news agency.

About 300 people took part in a protest urging an end to the security sweep, the official said. Chechen residents and human rights organizations have often accused Russian forces of arbitrarily rounding up men and teen-age boys during so-called mopping-up operations and abusing them.

Chechnya's chief prosecutor, Vsevolod Chernov, said Tuesday that the troops did not commit violations during their sweep of Argun, and claimed that 12 rebels had been killed in the operation, the ITAR-Tass news agency reported.

Meanwhile, a pro-Moscow official in the Vedeno district was shot to death in his home along with his father and son, the administration official said.

Four people were killed and three wounded Tuesday in an explosion in a house in the village of Starye Atagi, Interfax reported. Police were investigating whether it was a household gas explosion or a possible terrorist attack, the agency said.

Elsewhere in Chechnya, rebels attacked Russian outposts 21 times over the past 24 hours, killing three servicemen and wounding four, the official said. In Grozny, a jeep carrying security guards hit a land mine, killing one.

A police officer was killed and another wounded when their car was blown up Tuesday on a bridge in the Shali district, deputy district chief Abdula Sapiyev told Interfax.