Four police officers have been killed by a suicide bomber in the Russian republic of Chechnya, officials say.
The bomber reportedly walked up to a police car and blew himself in Mesker-Yurt, a town around 20km (12 miles) from the regional capital, Grozny.
Violence has continued despite Russian claims in April this year following a military campaign that Chechen rebels had been quelled.
Russian forces have been fighting separatists in Chechnya since 1994.
Chechen Interior Minister Ruslan Alkhanov said: "A suicide bomber blew up an improvised explosive device near a petrol station in Mesker-Yurt, in Shalinskiy District.
"His name is Magomed Shakhidov, who we detained in 2004, and who having served his time became engaged in terrorist activities."
The police officers who were killed were from the external security department in the town of Argun.
Three died at the scene and a fourth succumbed to his injuries later in hospital, said police.
Last Friday, two suicide bombers on bicycles killed four policemen in Grozny, in what the Chechen leader, Ramzan Kadyrov, said could have been aimed at killing him at a ceremony to mark his birthday.
Also, in neighbouring Ingushetia last week, suicide bombers killed 20 people and injured around 140 others.
Figures compiled by the BBC show that more than 400 people have died so far this year in the largely Muslim areas of Chechnya, Ingushetia and Dagestan.
One regional expert says there is no doubt the insurgencies in Chechnya and Ingushetia are now on the rise, with increasing numbers of young men, some still teenagers, joining militant organisations.