Two traffic police were killed in an attack by suspected Daesh terrorists in the southern Russian city of Astrakhan, the regional governor said Tuesday, the day after a suicide bomber allegedly hit the Saint Petersburg metro.

"Last night, a group of terrorists... carried out a brazen attack on employees of the traffic police," Alexander Zhilkin said in a statement.

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

Astrakhan regional police said the incident occurred at about 1:00am local time (2200 GMT) after traffic police were dispatched to the scene of an accident.

The attackers were in one of the cars involved in the accident.

The police statement made no mention of the attackers' motives or identity.

The Astrakhan region lies on the Caspian Sea and also borders the restive Caucasus region of Dagestan.

While attacks against police regularly occur in Russia's Caucasus, they are much rarer in other regions.