俄罗斯卫星网援引俄国家反恐委员会消息称：“据准确消息显示，爆炸导致11人死亡，45人在医院接受治疗。卫生部专家已经采取措施向伤者及其家人提供必要的医疗和心理援助。”
图为“技术学院”地铁站外警方封锁现场，救援直升机抵达。
俄罗斯侦查委员会已根据俄联邦刑法典205条(恐怖袭击)就圣彼得堡地铁爆炸提起刑事立案。调查也将对此事件的其他原因进行分析。
此前多家媒体曾报道说，爆炸发生在“先纳亚广场”地铁站、和该站附近的另一地铁站“技术学院站”。但俄罗斯国家反恐委员会负责人普里泽兹多姆斯基称，列车遭爆炸时，正运行在这两个地铁站之间。该委员会说，他们在另一地铁站“起义广场”找到了一个爆炸装置，并进行安全处理。
该委员会负责人普里泽兹多姆斯基说，爆炸发生在当地时间下午2点40分，是由“未经证实的爆炸装置”造成的，但事件真实原因尚在调查中。目前，俄罗斯当局已经为此开启了反恐调查，但爆炸的其它原因也没被排除。
图为“先纳亚广场”地铁站爆炸事件的伤员被抬上救护车。
国际文传电讯社称，地铁站的电眼可能捕捉到了袭击者的影像。该社引述一消息人士说，爆炸的装置可能是装在一个公事包内，留在出事列车的一节车厢内。据报，该土制炸弹的威力相当于200克的TNT当量，而且炸弹内可能藏有弹片。
上传到社交媒体的照片和视频显示，发生爆炸的车厢严重扭曲变形，有乘客在一节封闭的车厢内敲打车窗求救。一些伤亡者横躺在月台上，救援人员在场施救。其他人则纷纷逃离烟雾笼罩的车站。
爆炸事件导致周边地区陷入混乱，繁忙的莫斯科大街禁止车辆穿行，大批紧急救援车辆赶到出事地铁站外待命。
当地时间4月3日晚，俄罗斯民众在“先纳亚广场”地铁站前点燃蜡烛悼念地铁爆炸遇难者。王修君 摄
普京的发言人派斯科夫称，普京当天早些时候在圣彼得堡，但已离开该市。普京在会晤白俄罗斯总统卢卡申科时说：“我已经和情报部门的负责人通过话，他们将尽快查明事情原因。”
事发后，圣彼得堡关闭了该市所有的地铁站。同时，莫斯科的地铁站也加强了安保措施。
参与调查的高级调查官员佩德连科对俄罗斯媒体表示，爆炸发生后，那列地铁的司机果断决定继续行驶到下一站的做法挽救了很多人的生命，让救援工作能更快展开。MOSCOW --
A bomb blast tore through a subway train deep under Russia's second-largest city Monday, killing 11 people and wounding about 40 in a chaotic scene that left victims sprawled on a smoky platform. Hours later, anguish and fear rose again when police found and defused a shrapnel-packed explosive device at another St. Petersburg station.When the bomb blew on the metro car, Russian president Vladimir Putin was in his hometown of St. Petersburg for a meeting. He wasn't hurt, but dozens of others were and the death toll has climbed since the blast.
There was no immediate claim of responsibility for the attack, but in the past two decades, Russian trains and planes have been frequent targets of terrorism, usually blamed on Islamic militants.
The bomb was in a suitcase and exploded between stations on one of the city's north-south lines.
The area where the explosion occurred is famous as the backdrop of the famous Dostoyevsky novel "Crime and Punishment" in 1866.
After the blast, the subway train driver chose to continue on to the next stop. Authorities said that helped ensure a safe evacuation and prevented riders from maneuvering along the third rail.
"Terrible thing. Happening all over the world. Terrible thing," said President Donald Trump of the attack.
A few hours later panic spiked again after investigators found a second bomb at a different transit station. The devices were filled with nails and metal shards.
"Attacks like these on ordinary citizens just going about their lives reminds us that the world must work as one to combat violence in all forms. The United States is prepared to offer assistance to Russia that it may require in investigating this crime," said Press Secretary Sean Spicer.
News reports initially said police were searching for two suspects, and Russian state television showed a photo of one suspect wearing what appeared to be a skullcap characteristic of Russia's Muslim regions. However, the Interfax news agency later cited unspecified sources as saying police now suspect the blast was the work of a suicide bomber linked to radical Islamists.
The National Anti-Terrorism Committee said it was looking for the "perpetrators and organizers of the terror attack."
St. Petersburg, a major tourist destination famed for its imperial palaces and lavish art museums, had been spared previous attacks.
"From now on, I will be scared to take the subway," said Marina Ilyina, 30, who brought flowers to the station where the train stopped after the bombing. "We in St. Petersburg thought we wouldn't be touched by that."
The explosion occurred in midafternoon as the train traveled between stations on one of the city's north-south lines.
The driver chose to continue on to the next stop, Technological Institute, a decision praised by the Investigative Committee as aiding evacuation efforts and reducing the danger to passengers who would have had to walk along the electrified tracks.
The National Anti-Terrorism Committee said the death toll was 11, with another 45 people being treated for wounds in hospitals.
Amateur video broadcast by Russian TV showed people lying on the platform of the Technological Institute station, and others bleeding and weeping just after the damaged train pulled in.
"Everything was covered in smoke. There were a lot of firefighters," Maria Smirnova, a student on a train behind the stricken one, told independent TV station Dozhd.
Within two hours of the blast, authorities had found and deactivated another bomb at another busy station, Vosstaniya Square, the anti-terror agency said. That station is a major transfer point for passengers on two lines and serves the railway station to Moscow.
Russian law enforcement agencies confirmed the device was loaded with shrapnel, and the Interfax news agency said it contained up to 1 kilogram (2.2 pounds) of explosives.
Interfax cited an unidentified law enforcement official saying that investigators think the suspected suicide bomber left the bomb at the Vosstaniya Square station before blowing himself up on the train.
The agency said authorities believe the suspect, a 23-year old who came from ex-Soviet Central Asia and was linked to radical Islamist groups, carried the explosive device onto the train in a rucksack.
Asked about the report, Putin spokesman Dmitry Peskov wouldn't comment, saying it's up to law enforcement agencies to comment on details of the probe.
The entire St. Petersburg subway system was shut down and evacuated, but partial service resumed after about six hours.
Security was immediately tightened at all of the country's key transportation sites, Russia's National Anti-Terrorist Committee said. Moscow officials said that included the subway in the Russian capital.
Putin, who meeting with the president of Belarus at the Constantine Palace on the city's outskirts, offered condolences on national television.
"Law enforcement agencies and intelligence services are doing their best to establish the cause and give a full picture of what happened," a somber-looking Putin said.
He later laid flowers outside the Technological Institute station, where the damaged train arrived after the explosion.
Some residents of St. Petersburgh, a city of 5 million, responded with both dismay and determination.
"They won't succeed in breaking up our country. We are all citizens of one country despite various political views and religious beliefs," said 24-year-old Alexander Malikov, who brought flowers and candles to an improvised memorial outside one of the stations.
The bombing drew widespread condemnation.
President Donald Trump said it was "absolutely a terrible thing." White House Press Secretary Sean Spicer said the U.S. was prepared to offer assistance to Russia.
Lebanon's militant Hezbollah group, which is backing Syrian President Bashar Assad's forces along with Russia, says the incident was the type of "terrorism" Russia was fighting in Syria.
Most of the terrorist attacks in Russia have been connected to the insurgency in Chechnya and other Caucasus republics in the southern part of the country.
The last confirmed attack was in October 2015 when Islamic State militants downed a Russian airliner heading from an Egyptian resort to St. Petersburg, killing all 224 people on board.
The Dec. 25, 2016, crash of a Russian plane near the southern city of Sochi that killed 92 people, including members of the Red Army Choir, is widely believed to have been due to a bomb, but no official cause has been given.
Two female suicide bombers killed 40 people and wounded more than 100 in the Moscow subway on March 29, 2010. Chechen rebel leader Doku Umarov claimed responsibility for the attack, warning Russian leaders that "the war is coming to their cities."
A Moscow-to-St. Petersburg train was bombed on Nov. 27, 2009, in an attack that left 26 dead and 100 injured. Umarov's group also said he ordered this attack.
Russian airports also have been targeted. On Jan. 24, 2011, a suicide bomber blew himself up at Moscow's Domodedovo Airport, killing 37 people and wounding 180. The same airport in August 2004 saw Islamic suicide bombers board two airplanes and bring them down, killing a total of 90 people.
WLS-TV contributed to this report.
ABC News contributed to this report.
