Governments around the globe are condemning today's (Friday's) subway bomb blast in Moscow that killed at least 39 people.
President Bush denounced the blast in the strongest terms during a conversation with President Putin, and the two vowed to boost their anti-terrorism efforts.
U.N. Secretary-General Kofi Annan said he was appalled, adding no cause could justify such a heinous crime. Leaders from the European Union and Japan have also condemned the bomb attack.
The explosion, which wounded at least 130 people, ripped through a train during morning rush hour and sparked a fire. Moscow's deputy mayor (Valery Shantsev) said the blast had the force of about five kilograms of T-N-T.
Moscow police say they suspect it was a suicide bombing, but are looking into other ways the bomb could have been delivered. Police are searching for a middle-aged man who is believed to be a native of the Caucasus region.
Just after the blast, Mr. Putin suggested Chechen separatists were responsible, saying they are to blame for the terrorism that plagues Russia. But the Chechen rebel leadership issued a statement condemning the blast and denying involvement.
The explosion comes five weeks ahead of presidential elections in Russia that Mr. Putin is expected to win.
Suicide bomb attacks in Russia have become the trademark of Chechen separatist rebels battling Russian rule over their homeland in the Caucasus.
In December, a suicide bomber blew herself up outside Moscow's famed National Hotel, just across from Red Square and the Kremlin, killing five people and herself. Two Chechen suicide bombers blew themselves up at a Moscow rock concert in July, killing 14 people.
Information for this report is provided by AFP and Reuters.