Russian President Vladimir Putin pledged Monday to find terrorists in "the basements and caves where they are hiding and destroy them" after a double suicide bombing at a Moscow rock festival, while human rights groups cautioned against an excessive response to the tragedy that could incite further tension.
In a meeting with his Cabinet, Putin said Russia wouldn't bow to terrorist demands and linked the attacks to unspecified international terrorist organizations.
No group has claimed responsibility for the Saturday attack that killed 13 and two female bombers, but officials have said a passport found at the site was from a Chechen woman whose family is linked to one of the many armed groups fighting in Chechnya.
"Today, after the latest series of terrorist acts, we can say that the bandits active in Chechnya are not simply connected with international terrorist organizations, they have become an integral, maybe the most dangerous part, of the international web," Putin said in remarks shown on Russian television.
"No country in the world bows to the dictates of terrorists and Russia will not do so either," Putin said. "We must pluck them out from the basements and caves where they are hiding and destroy them."
Putin's typical brash vows of action prompted international human rights groups condemning the attacks to also plead for Russian authorities' response to be proportional and in accordance with international law.
Both Amnesty International and the International Helsinki Federation for Human Rights noted increasing harassment and arbitrary arrests of Chechens and other Caucasus people after a theater hostage-taking in Moscow last October. Special forces ended the standoff by using a powerful narcotic gas that killed most of the 129 hostages who died there.
"The brutal conflict in Chechnya generates violence such as that witnessed in Tushino," the airport that was site of the Saturday attack, the Helsinki Federation said in a statement.
Human-rights groups have repeatedly criticized Russian forces' tactics in Chechnya, where the latest war has dragged on for nearly four years.
Also Monday, Russian troops claimed to have killed five rebels at a suspected terrorist training camp where say they found devices similar to those used by the two suicide bombers, ITAR-Tass news agency reported.
Thirty-eight of the 59 people injured in the blasts remained hospitalized Monday.
Moscow Mayor Yuri Luzhkov said relatives of those killed would receive 100,000 rubles (US$3,300) in compensation.