Two traffic police officers have lost their lives in a shooting attack in the southern Russian city of Astrakhan, as Russians are still in a state of shock following a bomb blast in Saint Petersburg metro that left over a dozen people dead and scores of others wounded.

Axar.az reports that the deadly incident occurred during the early hours of Tuesday after a “group” of radicalized assailants “carried out a brazen attack on employees of the traffic police,” said Alexander Zhilkin, Governor of Astrakhan Oblast, in a statement.

“The culprits opened fire on them with firearms and fled. Unfortunately, two traffic police officers died on the spot,” he added.

According to Astrakhan's regional police, the assault took place at about 1:00 a.m. local time (2200 GMT) after some traffic police officers were dispatched to the scene of a car accident. It added that the assailants were in one of the vehicles involved in the accident, but it did not elaborate on the attackers’ motives or identity.

Later in the day, Russia’s Interior Ministry said in a statement that the two suspected attackers had been arrested.

Astrakhan is located on the Caspian Sea, bordering the volatile Caucasus region of Dagestan.

The shooting attack happened hours after a metro explosion in St. Petersburg killed 14 people and injured almost 50 others. The carnage was caused by a bomb that had been detonated by a man whose body parts were found in one of the train carriages.