PRAGUE — An unknown perpetrator threw several Molotov cocktails at a Russian cultural center in Prague late Thursday, Czech police said. The building did not catch fire, according to police.

Three of the six Molotov cocktails did not explode, Igor Girenko, director of the Russian cultural center, told Tass.

A photograph shows a broken window and two windows and a wall partly covered with smoke at the Russian cultural center, known as the Russian House. The building is funded by the Russian state but does not have diplomatic status.

Russian Foreign Ministry spokeswoman Maria Zakharova called the attack a barbaric act. Czech Interior Minister Lubomír Metnar called the attack unacceptable.

The Russian embassy in Prague asked Czech authorities to boost security for Russian institutions and employees in the country following the attack.

The Russian House organizes various cultural, educational and scientific programs and offers Russian language courses, according to the center.