There is no evidence they are connected with Akbarzhon Jalilov, a Kyrgyzstan-born man suspected of bombing St Petersburg's metro.
Djalilov's "genetic trace" was also found on a bag containing a second bomb left at another metro station and later defused, the statement said.
Links between those arrested and the bomber are still being investigated, the agency said, but added that "clues" had been found at the suspected accomplices' addresses.
The six come from former Soviet Central Asian republics. "The recent tragic events in St. Petersburg are the best confirmation of this", Putin said at the meeting in Moscow.
"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. A bomb blast tore through a subway train under Russia's seco.
The explosion happened between Sennaya Ploshchad and Tekhnologichesky Institut stations.
The statement said the authorities had not yet decided whether to press charges against the detainees.
While most Central Asian migrants in Russia hold temporary work permits or work illegally, thousands of them have received Russian citizenship in the past decades.
Commuters on the busy Saint Petersburg metro remained on edge after the system temporarily shut down Monday in the wake of the attack.
Philippines quake sparks mass evacuation and tsunami fears
Office workers in the capital of Manila , about 68 miles away, were seen rushing out of buildings after feeling the tremors. Photo taken by Ryan Panganiban Valle, shows the damaged wall of a building at the Camp Netanya Resort in Mabini, Batangas .
Here's When Apple Watch Series 3 May Debut
In 2016 Apple analysts estimated that the Cupertino, California-based technology giant shipped more than 11 million smartwatches. It has, however, been diversifying in the last few years and some of these efforts have been paying off.
Hyundai announces all-new Kona
The Kona will therefore be the smallest member of a family that also includes the Grand Santa Fe , the Santa Fe and the Tucson. Its true SUV genes, progressive design and premium features enhance the brand's appeal to attract new customers.
The bomb went off Monday afternoon as the train was moving between two stations.
President Donald Trump called President Vladimir Putin late Monday to express his condolences, Kremlin spokesman Dmitri Peskov said, but the conversation was limited to expressions of support.
"I traveled on the same route this morning just to see how it felt and think about life".
Petrov was also a hand-to-hand champion of St. Petersburg and the Leningrad region, an Army hand-to-hand combat champion of Russian Federation, and had a brown belt in Kyokushin karate.
One of those stations was closed by a bomb threat Tuesday and again on Wednesday as officials checked for anything suspicious.
Patriach Kirill, head of the Russian Orthodox Church, led a service at Moscow's main cathedral on Tuesday for the bombing victims.
No one has claimed responsibility for the bombing, but Russian trains and planes have often been targeted by Islamist militants.
According to the Investigative Committee of Russian Federation on Wednesday, the suspects were accused of recruiting people for terror groups such as the Islamist former al-Qaida branch Jabhat Fateh al-Sham (formerly known as the Nusra Front) and the IS, Efe news reported.
Separately, in the southern Russian city of Astrakhan, two policemen were killed in the early hours on Tuesday in a suspected Islamic militant attack.
Tickets were written for talking on a cellphone without a hands-free device, texting or using an electronic device while driving. The national campaign slogan is "You Drive, You Text, You Pay", but it's not all about texting.
But, during the interview , Rice was less than open about whether she would willingly cooperate with questioning by the Congress. It is not too soon to begin asking, what did Barack Obama know and when did he know it?
I didn't see you raising your voice against President Obama's inaction in Syria that...made us refugees get kicked out of Syria. McMaster said Thursday when asked about the refugee policy. "Cruise missiles alone are not a solution", said Rep.
Two of the three Russians charged in the 2015 case were operating under diplomatic cover and evaded prosecution. This is intelligence method to cheat, how else to work with foreigners? "You promise him a favor for a favor".
Europe and Asia will be the next two to host a World Cup , which means they won't be able to bid for the next tournaments. Trump has also signed an executive order barring travelers from six Muslim-majority nations from entering the U.S.
On Monday, the company launched Amazon Cash, where users can add to their balance at a participating brick-and-mortar retailer. If a customer does not receive a notification, Amazon says they should first discuss the issue with the retailer they visited.
Julian Nagelsmann's men staged a faultless performance against the German giants and dictated the pace in the first half. Dortmund created a number of opportunities, but Rene Adler denied Aubameyang several chances to extend the lead.
Spotify didn't say if Jay Z's decision was based on friction between Tidal and other streaming music services. Last year, his 2001 album " The Blueprint " was also removed from all streaming services other than Tidal.
But it cautioned that genetic risk is just one piece of information and does not mean they will or won't eventually get a disease. In addition, this may nudge them to make key changes in their lifestyle choices to minimize the incidence of these diseases.
Still, there were reports that Gotch had a problem with speaking out , and "Gotch's mouth sometimes gets people mad at him". All that was said was that Gotch was gone as of April 5, 2017 , and they wished him the best "in all his future endeavors".
Mourinho explains why De Gea didn't play against Sunderland
Manchester United's evergreen striker believes he is football's answer to the fictional character who reverses the ageing process. But Ibrahimovic added: "It was an important three points, especially after games when we haven't got what we wanted".
Gunman killed after 'shooting two people at an Equinox'
Witnesses identified the gunman as a 33-year-old trainer, and those wounded were the general manager and a trainer, it said. Wilson had apparently been let go by the Equinox fitness center in Coral Gables but showed up Saturday in his uniform.
KC police ID 2nd body found by missing woman's relatives
Jessica Runions, 21, was last seen in September 2016 and her SUV was found burned along Blue River Road in south Kansas City. She also alleged Yust told her that he had killed her three cats and would kill her family if she reported him to the cops.
Mel B Files Restraining Order Against Ex, Claiming He Beat and
However, speaking to TMZ's photographers on Monday, Belafonte denied all the claims, saying, "I'm shocked at those allegations". In the statement, Mel claims that Stephen punched her with his fist because she was set to do an X-Factor segment with Usher.
Smith leads Pune chase to beat Mumbai in IPL opener
Kieron Pollard was dismissed for 27 (17 balls; 3x4; 1x6) in the penultimate over by Stokes for the bowler's first IPL wicket. Steve Smith heaped praise for leggi Imran Tahir , who took three wickets to restrict Mumbai to 184 for 8.