ISTANBUL - "We did not carry out the attack in Moscow, and we don't know who did it," Shemsettin Batukaev, a spokesman for the Caucasus Emirate organization, told Reuters by telephone in Turkey.

The spokesman said the group planned attacks on economic targets inside Russia, but not against civilians. Its leader, Doku Umarov, vowed last month to spread a Caucasian insurgency to Russian cities.

The Caucusus Emirate aims to create a pan-Caucasus, sharia-based state separate from Russia. Security analysts have named it as a potential suspect in Monday's attacks, which Russian authorities have blamed on female suicide bombers with connections to the volatile North Caucasus region.

No one has yet claimed responsibility for Moscow's worst bomb attack in six years.

"Of course we plan on attacking Russian economic targets, but our plans do not include attacks on people," said Batukaev, who lives in Istanbul and acts as the group's foreign representative.

He said he also did not know who was behind two bombings in Dagestan that killed 12 people on Wednesday, but did not deny the possibility that his organization was involved.

The bombings highlight problems Russia has faced in trying to stem rising violence in the North Caucasus insurgency, which is likely to be at the heart of a 2012 presidential election.

The Kremlin had declared victory in its battle with Chechen separatists who fought two wars with Moscow. But violence has intensified over the past year in the neighboring republics of Dagestan and Ingushetia, where Islamist militancy overlaps with clan rivalries, criminal gangs and widespread poverty.

Russian Prime Minister Vladimir Putin, who gained popularity by crushing the second Chechen insurgency, said the culprits behind the bombings should be "scraped from the sewers".

Batukaev, speaking by telephone, said the attacks could have been the work of individuals "filled with enough hatred.

"There are lots of Chechens who would happily have thrown an atom bomb into the subway. There are many people filled with enough rage out there who could have done this," he said.

"But these people do not represent us," he said.

The Chechen rebellion began in the 1990s as a largely ethnic nationalist movement. Russian officials say Islamic militants from outside Russia have joined the campaign, most after the secong war, giving it a fresh intensity.

Batukaev said there were a few foreigners fighting with the insurgents but his organization did not have ties to foreign Islamist groups, like al Qaeda, and relied on sympathizers at home for funding.