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Input: Russian President Vladimir Putin  says an explosion at a St. Petersburg supermarket on Wednesday was a terrorist act  and that another attack in the city had been foiled by the country's security service.
A bomb went off in a branch of the Perekrestok supermarket  wounding at least 13 shoppers in  Putin 's hometown  Reuters reports:
No group has taken responsibility for the explosion. A spokesman for  Putin   Dmitry Peskov  would not say why authorities believed it to be terrorism  but said because the bomb was packed with shrapnel proved it "was a terrorist attack anyway." Investigators said the device contained 7 ounces of explosives.
A Kremlin spokesman told Reuters that the thwarted attack  Putin  referenced was the one earlier this month that targeted St. Petersburg's Kazansky Cathedral. The Federal Security Service said seven suspects linked to ISIS have been arrested in connection with that plot.  Putin  had called Donald Trump and thanked  him  for the CIA tip that led to the capture of the suspects.
On Thursday  Putin  said that the operation in Syria had reduced the threat of attacks in Russia  functioning as a preemptive strike against terrorists.
"What would have happened if those thousands (of terrorists) that I have just spoken about  hundreds of them had come back to us  trained and armed "  he  said in comments to Russian news agencies  The Associated Press reports.

Putin Says St. Petersburg Blast Was Terrorism