Russian authorities have made safe an explosive device found in a residential building in St. Petersburg, the TASS news agency reported on Thursday.
A law enforcement source told Reuters that fire engines had turned up at the building in question and that people living in flats on two stairwells had been evacuated.
The city is still reeling after a bomb ripped through the St. Petersburg metro on Monday, killing 14 people.
An explosion in the southern Russian city of Rostov-on-Don early Thursday, injured one person, a law enforcement source told TASS.
REN-TV cited witnesses as saying that the explosion happened near a school on Sadovaya Street and that a maintenance worker was injured in the blast.