Four Ukrainian servicemen have been injured in the active phase of the anti-terrorist operation launched in Mariupol, Donetsk region, on Friday morning, the Ukrainian National Guard said in a statement posted on its Web site.

"Four special unit servicemen are injured, and one is in serious condition," the report runs.

"Heorhiyivska Street has been cleared of terrorists, and yards of nearby private houses are being searched. The special operation continues," it says.

The National Guard and Interior Ministry special units Dnipro and Azov are engaged in the operation.

"The National Guard reported that every key stronghold of the terrorists had been taken under control, an armored reconnaissance vehicle had been blown up, sniper positions had been destroyed, and occupied buildings had been freed. A land mine found on Heorhiyivska Street in the center of Mariupol is being defused. A demolition squad is at work," the report says.