Russian President Vladimir Putin remained conspicuously quiet Sunday on a deadly suicide attack at a Moscow rock concert which served as a clear sign that his moves towards peace in breakaway Chechnya were not going according to plan.

Putin issued condolences to the families of people who died Saturday when two female suicide bombers blew themselves up at the concert's ticket booth, killing at least 16 other people and injuring around 50 others.

But the Russian leader has made no comment since then.

Officials immediately said the suicide blasts were the latest in a series of deadly attacks carried out by Chechen separatist rebels aimed at disrupting Russian plans to pacify the war-ravaged republic.

Putin coasted into the Russian presidency nearly four years ago after taking a hard line with Chechnya, launching the second war in the republic in October 1999 while serving as prime minister.

Yet with increasingly loud worries over the number of young Russian soldiers killed in the

drawn-out war, Putin is keen to have the Chechen conflict seen as settled by the time he faces reelection next March.

Interior Minister Boris Gryzlov told journalists Saturday that the blast was likely linked to Putin's signing earlier Saturday of a decree setting Chechnya's presidential elections for October 5.

"Today the president signed a decree on elections in Chechnya, and one can think that these attacks are linked to this event," Gryzlov said.

Chechen voters approved carrying out presidential and subsequent parliamentary elections in a March referendum.

They also voted to confirm the republic's place within the Russian Federation, prompting Puin to declare the war was over.

Yet that declaration has been questioned after a series of suicide attacks in Chechnya over the past few months that have killed some 100 people.

A medical source quoted by Interfax news agency said 48 people had been hospitalized after the rock concert attack, most with shrapnel wounds from the suicide belts.