A shopping centre explosion in the home country of the Boston marathon bombers has killed two people.
The blast came in a busy area of Makhachkala, capital city of the Russian republic of Dagestan, and several other people were injured.
The bomb went off when two teenage boys tried to open a cardboard box left near a store and both of them were killed.
Dagestan is plagued by Islamic insurgents who frequently mount small attacks on police and security forces, with bombs often placed in cars or along roads. The latest explosion, however, was unusual in that the target was not clear.
A day earlier three policemen were killed and another one was wounded when their vehicle came under fire in the town of Buinaksk.
The republic in southern Russia is home to the parents of the suspects in last month's Boston Marathon bombing. One of the suspects, who was killed in a shoot-out with Boston police, paid a long visit to Dagestan last year and investigators are trying to discover if he had contact with extremists there.