MOSCOW, June 17. /ITAR-TASS/. Organizers of the attack on the Russian Embassy in Ukraine’s Kiev last week must be found and punished, speaker of the Russian parliament’s upper house Valentina Matviyenko said on Tuesday as she condemned the incident.

The building of the Russian Embassy in the Ukrainian capital came under attack of radically inspired crowds late on Saturday night. Embassy staff’s cars were overturned and smashed to smithereens, the Russian national flag was torn down and the outside walls of the facility were pelted with eggs, smoke barrels and firecrackers. Windows were shattered with thrown chunks of concrete.

“The attack on the diplomatic mission is an unprecedented and outrageous act,” Valentina Matviyenko, the speaker of the Federation Council, said. “It contradicts the Vienna Convention on the protection of diplomatic missions.”

The senior lawmaker, however, said the diplomatic relations between neighboring Russia and Ukraine should be maintained.

“We definitely need to maintain diplomatic relations, but we [Russia] expressed our position and the Ukrainian authorities assured us that they would handle the situation and find those guilty,” Matviyenko said. “We need to understand who was behind that incident and the guilty must be held responsible.”

Matviyenko added that the diplomatic contacts must be also maintained to continue negotiations with Ukraine on putting an end to the punitive operation in the southeast of the country.

Fierce fighting has been underway between the Ukrainian military and militias in Ukraine’s southeastern Donetsk and Luhansk regions, which refused to recognize the authorities who had been propelled to power amid riots during a coup in Ukraine in February 2014.

A punitive operation, being conducted by Kiev against federalization supporters in Ukraine's southeast regions and involving armored vehicles, heavy artillery and attack aircraft, has already claimed hundreds of lives, including among civilians.

Billionaire businessman and politician Petro Poroshenko, who had funded anti-government protests that led to February’s coup, won the May 25 early presidential election in Ukraine, set earlier by the provisional Kiev authorities. He was sworn in on June 7. Despite hopes that the punitive operation will stop under Poroshenko, it still continues.