The woman in the white coat appeared to be a first aid worker

Video footage shows a woman apparently trying to calm a grieving woman who is being restrained by uniformed naval personnel as she demands to know the truth.

"Why did he die? He served for 25 years! I'll never forgive you!" the grieving relative shouted.

The woman who appeared to be giving first aid is then seen holding a syringe, which she appears to plunge into the grieving woman behind her back.

Naval officers moved in when the woman began haranguing officials

Seconds later the widow - still being restrained by naval officers - collapses, apparently under the influence of a powerful sedative.

The footage was shot by a Murmansk television cameraman, Alexander Glokov. He told the BBC that soon after the incident the authorities ejected him from the hall.

The hall was packed with naval officers in anticipation of some emotional scenes, he said.

The BBC correspondent Orla Guerin says the incident carried echoes of a past from which Russia has not yet fully escaped.

The woman in the white coat is seen holding a syringe

She says the woman may have needed medical help, but the drug was apparently administered without her consent.

Dissidents in the Soviet Union were sometimes given powerful drugs normally only reserved for people suffering genuine mental illness.

Neither officials of the Russian Northern Fleet nor the Russian Defence Ministry were willing to comment on the incident, our correspondent says.

A Russian embassy official, Vladimir Andreyev, told the BBC it was "nonsense" to claim that Russia was reverting to old traditions of silencing dissent.

He said the "wrong medical practice may have been used in this case," but it was "not a violation of human rights".

Bereaved relatives are getting constant medical attention

The BBC's Russian affairs analyst Stephen Dalziel says it is common practice in Russia to sedate hysterical people without their consent.

Attempts to tie the incident in with a return to Soviet KGB practices are though wide of the mark, he says.

Relatives of the dead sailors have had doctors and nurses close by all the time, the BBC's Rob Parsons reports from Murmansk. Some people were sedated when the medical staff deemed it necessary.

About 150 bereaved relatives held an emotional memorial ceremony in the Barents Sea on Thursday, lowering flowers into the waters where the Kursk sank on 12 August.

Mr Andreyev said the Russian Government was ready to answer all the bereaved relatives' questions about the disaster.