Russian Prime Minister Vladimir Putin vowed a fierce response Monday after two female suicide bombers blew themselves up in twin attacks on Moscow subway stations, killing at least 37 people and wounding 102. Officials blamed the carnage on rebels from the Caucasus region.Prime Minister Binyamin Netanyahu issued a statement where he expressed Israel’s solidarity and sympathy with the Russian people.“In the name of all of Israel, please receive our condolences to the families of the murdered and our wishes of full recovery to the wounded. We condemn the terror attacks which caused so much grief to innocent civilians."“As a nation that is a target to terror attacks, Israel expresses its deep solidarity and companionship with the Russian people in its hour of grief; we stand united with all enlightened nations in the struggle against terrorism which threatens all of human society,” Netanyahu said.Ina statement issued by the White House early Monday, the president saidthe American people stand united with the people of Russia inopposition to violent extremism and "heinous" terrorist attacks.In a phone call to President Medvedev to offer condolences following the attacks, President Obama went on to say that "the United States was ready to cooperate with Russia to help bring to justice those who undertook this attack," the White House said in a statement quoted by Reuters.The blasts come six years after Caucasus Islamic separatists carried out a pair of deadly Moscow subway strikes and raise concerns that the war has once again come to Russia's capital, amid militants' warnings of a renewed determination to push their fight.Past bombings on the Moscow subway systemChechen rebels claimed responsibility for a deadly bombing late last year on a passenger train en route from Moscow to St. Petersburg.Putin, who built much of his political capital by directing a fierce war with Chechen separatists a decade ago, vowed Monday that "terrorists will be destroyed."The first explosion took place just before 8 a.m. at the Lubyanka station in central Moscow. The station is underneath the building that houses the main offices of the Federal Security Service, or FSB, the KGB's main successor agency.A second explosion hit the Park Kultury station about 45 minutes later."I heard a bang, turned my head and smoke was everywhere. People ranfor the exits screaming," said 24-year-old Alexander Vakulov, who saidhe was on a train on the platform opposite the targeted train at ParkKultury."I saw a dead person for the first time in my life,"said 19-year-old Valentin Popov, who had just arrived at the stationfrom the opposite direction.The iconic Moscow subway system isone of the world's busiest, carrying around 7 million passengers on anaverage workday, and is a key element in running the sprawling andtraffic-choked city.Russian TV showed amateur video from insidethe Lubyanka station of wounded and possibly dead victims sitting andlying on the floor. The train platform was filled with smoke. Outsideboth stations, passengers flooded out, many of them crying and makingfrantic calls on their cell phones. The wounded were loaded intoambulances and helicopters, some with their heads wrapped in bloodybandages, as sirens wailed.The last confirmed terrorist attackin Moscow was in August 2004, when a suicide bomber blew herself upoutside a city subway station, killing 10 people. Responsibility forthat blast was claimed by Chechen rebels.Russian police havekilled several Islamic militant leaders in the North Caucasus recently,including one last week in the Kabardino-Balkariya region. The killingof Anzor Astemirov was mourned by contributors to twoal-Qaida-affiliated Web sites.The killings have raised fears of retaliatory strikes by the militants.InFebruary, Chechen rebel leader Doku Umarov warned in an interview on arebel-affiliated Web site that "the zone of military operations will beextended to the territory of Russia ... the war is coming to theircities."Umarov also claimed his fighters were responsible forthe November bombing of the Nevsky Express passenger train that killed26 people en route from Moscow to St. Petersburg.EmergencyMinister Sergei Shoigu said the toll was 37 killed and 102 injured, buthe did not give a breakdown of casualties at each station.In atelevised meeting with President Dmitry Medvedev, Federal SecurityService head Alexander Bortnikov said body fragments of the two bomberspointed to a Caucasus connection. He did not elaborate."We will continue the fight against terrorism unswervingly and to the end," Medvedev said.Neitherhe nor Putin, who was on an official trip in Siberia, announcedspecific measures and it was not clear if Russia has new strategies tounleash in the Caucasus, where violent separatism has spread fromChechnya into neighboring republics.Although the Russian armybattered Chechen rebels in massive assaults a decade ago, theseparatists continue to move through the region's mountains and forestswith comparative ease and launch frequent small attacks.NewYork's transit system beefed up security as a precaution following theMoscow bombings. A spokesman for New York's Metropolitan TransportationAuthority, Kevin Ortiz, said the agency has a "heightened securitypresence," but declined further comment.The agency is in charge of New York City buses and subways, as well as suburban trains, and bridges and tunnels.The Moscow blasts practically paralyzed movement in the city center as emergency vehicles sped to the stations.Inthe Park Kultury blast, the bomber was wearing a belt packed withplastic explosive and set it off as the train's doors opened, saidVladimir Markin, a spokesman for Russia's top investigative body. Thewoman has not been identified, he told reporters.A woman whosells newspapers outside the Lubyanka station, Ludmila Famokatova, saidthere appeared to be no panic, but that many of the people who streamedout were distraught."One man was weeping, crossing himself, saying 'thank God I survived'," she said.