Rescuers have called off the search for survivors of a suicide truck bombing attack on a military hospital in southern Russia.
Soldiers serving in Chechnya received treatment at the hospital
On Sunday, the body of a surgical nurse was pulled out from beneath the rubble - the 50th person known to have died in the blast which also injured 72 others.
Officials have blamed separatist Chechen rebels for the attack which occurred in the military town of Mozdok, in North Ossetia.
The officer in charge of the hospital has been detained on suspicion of criminal negligence.
Russian Defence Minister Sergei Ivanov who went to Mozdok on the orders of President Vladimir Putin, said that despite recent instructions, no measures had been taken to block access to the hospital by unauthorised vehicles.
The suicide bomber was able to drive a truck packed with ammonium nitrate explosive to the hospital's front doors and detonate it.
"There is no longer a chance of finding anyone alive. We may pull out some parts of bodies," a rescue worker told the French news agency AFP on Sunday.
Mr Putin - who refuses to deal with the Chechen rebels - has sent a letter of condolence to the victims' families.
"The terrorists will not be able to dictate their criminal ways
upon us. Their bloody crimes will not end the political peace process," he said in a statement.
A spokesman for the moderate rebel Chechen leader Aslan Maskhadov has said the Chechen leadership was not involved in the attack, but that he could not speak for other groups.
Friday's bomb was the bloodiest since May, when a truck bomb attack in Chechnya killed 60 people.
Last month, 15 people were killed at a rock concert in Moscow when two female bombers blew themselves up.
The BBC's Sarah Rainsford in Moscow says this latest attack is another blow to the Kremlin, which claims to have the situation in Chechnya under control.
The separatists have rejected Moscow's plans for presidential elections in October and have vowed to resist Russian forces there.