Prime Minister Vladimir Putin said Wednesday that those behind a deadly suicide attack on Moscow's busiest airport were unlikely to have come from Russia's southern republic of Chechnya.

This terrorist act, according to preliminary data, has no relation to the Chechen Republic, Putin told reporters.

Putin, who launched a war against Chechen rebels in 1999, refused to clarify his comment, which is likely to prompt speculation that the attackers came from another republic in Russia's insurgency-plagued North Caucasus, such as Ingushetia or Dagestan.

No group has yet claimed responsibility for the attack which killed at least 35 people and injured more than 100.

Russia Vladimir putin Putin