Rescuers yesterday called off the search operation for victims of a suicide truck-bomb blast, after pulling the body of a surgical nurse out of the ruins of a military hospital near Chechnya. They said hope had disappeared of finding any survivors in the rubble.

　　With the discovery of the nurse's body and at least four others overnight, the death toll rose to 50, said Lieutenant Colonel Yuri Miroshnichenko, spokesman for the Emergency Situations Ministry in southern Russia. Sixty-four injured remained hospitalized, he said.

　　Authorities said they didn't expect to find any more bodies and the operation switched to a clean-up effort at the site of the four-story brick hospital, which collapsed like a house of cards when an unidentified driver rammed a truck full of explosives into it on Friday night.

　　Russian officials said they suspected Chechen rebels were behind the attack at the hospital in the North Ossetian city of Mozdok, since it bore similarities to other blasts and targeted a facility treating Russian soldiers injured fighting in Chechnya.

　　Russian president Vladimir Putin vowed on Saturday that terrorists acts will not stop what he called efforts aimed at fostering peace in Chechnya, where Russian forces have battled separatists in two wars during the last decade.

　　In a condolence telegram, Putin called the bombing "yet another confirmation of the inhumanity and cruelty of the bandits who are trying to destabilize the situation in the Northern Caucasus" - the region that includes Chechnya. A series of suicide bombings blamed on Chechen rebels - including last month's double suicide bombing at a rock festival in Moscow - have killed about 150 people since May.

　　"But the terrorists will not succeed in imposing their criminal will," said the telegram, which was distributed by Putin's press service.

　　The friday attack prompted ansgroupsfor round-the-clock patrols at hospitals, oil and energy facilities and major buildings across Chechnya, the ITAR-Tass news agency said.

　　The emergency Situations Ministry said yesterday that the dead included at least 22 military personnel. Earlier figures also noted that at least 12 local residents and eight hospital workers were among the dead.