A Ukrainian lawmaker wounded in an explosion in Kyiv that killed two people blamed Russia on Thursday for the blast, while officials said they were considering various motives for what they called an act of terrorism.

Ihor Mosiychuk, a member of the populist opposition Radical Party, was hospitalized but did not suffer life-threatening injuries, while his bodyguard and a passerby were killed. Two others were wounded. Ukraine's state security service (SBU) said unknown perpetrators had rigged a motorcycle with explosives that detonated as the lawmaker left a TV station.

Radical Party Leader Oleg Lyashko said he had no doubt the incident was politically motivated, while Mosiychuk blamed Russia.

"I believe that the initiators are in Moscow, the executors are in Kyiv," Mosiychuk said on Facebook.

Russian involvement is one of the possible motives being investigated, deputy Kyiv prosecutor Pavlo Kononenko told journalists.

"Another explanation is Mosiychuk's political activity, his public position within our country," said Kononenko. "A third explanation is an attempt on Mosiychuk's life for personal reasons."

Since fighting with pro-Russian separatists in eastern Ukraine broke out in 2014, the number of incidents involving explosives outside the conflict zone has increased, but vehicle bombings in the capital are relatively rare.

In June, a colonel in Ukraine's military intelligence was killed by a car bomb in central Kyiv. In 2016 a prominent investigative journalist, Pavel Sheremet, was killed by an explosive device in his car.

Radical Party lawmaker Evhen Deidei posted photos on his Facebook page from the scene of Wednesday's attack which showed the burnt-out shell of a motorcycle in front of a damaged vehicle.

"Judging by the damage to the car and the shrapnel holes in the doors, the power of the explosion was pretty strong," he said. "There is a lot of blood on the stairs, where Ihor was situated at the time of the explosion.

Shkiryak said political analyst Vitaliy Bala was one of the three wounded in the blast.