Ukrainian Security Service (SBU) officer Oleksandr Kharaberiush died in a car explosion in Mariupol on Friday morning, Ukrainian Security Service chief Vasyl Hrytsak has said.

"A car was blown up in a Mariupol residential area at about 8:30 a.m. today, killing Ukrainian Security Service Col. Oleksandr Kharaberiush," the service quoted Hrytsak as saying.

"The Ukrainian Security Service will do its best to find and punish the culprits. Our payback is always prompt," Hrytsak said.

Eyewitnesses said Kharaberiush's Toyota SUV was completely destroyed by fire, and windows were smashed in some buildings around the blast scene.

Kharaberiush was the Ukrainian Security Service's deputy counterintelligence chief in the Donetsk region, a source told Interfax-Ukraine.

The explosion occurred at the junction of Metalurhiv Avenue and Kafaiska Street in the central district of Mariupol at 8:35 a.m., the Donetsk regional police's liaison department said. Regional police chiefs, an investigative team, State Emergency Service employees, bomb technicians and forensic specialists are working on the crime scene. The area has been cordoned off by Mariupol patrolmen.

The explosion causes have yet to be determined, and an inquiry is in progress.

Viacheslav Abroskin, chief of the National Police department in the Donetsk region, said on Facebook a terror attack perpetrated by a sabotage-and-reconnaissance group from the self-proclaimed Donetsk People's Republic (DPR) was being pursued among the possible theories of the explosion. Police patrols are being reinforced in Mariupol and across the Donetsk region, he said.