Russia ? An explosion hit a McDonald’s restaurant in central St. Petersburg on Sunday, injuring at least six people, officials said.

Eyewitnesses said the blast went off in the handbag of a restaurant patron, according to Ekho Moskvy radio.

The explosion blew out windows at the restaurant and partially destroyed the ceiling, said Irina Andriyanova, spokeswoman for the Emergency Situations Ministry.

Officials did not say whether they believed the explosion was related to terrorism or a criminal act. McDonald’s restaurants have been targets of both criminal gang disputes and terrorist attacks in Russia in the past.