The scene of the bombing
A suicide attacker has killed at least two police officers in the Russian republic of Ingushetia, in the latest in a series of such bombings.
Shortly after the first attack, a car bomb was detonated in the same place in the town of Karabulak, officials said.
Forty were killed by a twin attack on Moscow's Metro system last week, and another North Caucasus republic, Dagestan, has also been targeted.
The Kremlin blamed Islamists from the North Caucasus for the earlier attacks.
Russian media reports have published images of a woman they say carried out one of the attacks in Moscow, saying she was from Dagestan.
Police officials said the bombings in Ingushetia had targeted an interior ministry building.
A statement from investigators said the suicide attacker had detonated explosives as a car full of police officers was entering the compound at 0820 local time (0420 GMT).
"As a result of the blast, the suicide bomber died at the scene and three police officers were taken to hospital, where two of them died," AFP news agency quoted the statement as saying.
Less than an hour later, as investigators arrived at the scene, a remote-control car bomb was detonated.
Officials said no-one was hurt in the second explosion.
Russia became embroiled in a bitter conflict with Islamist separatists in the North Caucasus republic of Chechnya in the late 1990s.
The violence spilled over to Ingushetia and Dagestan and, although Moscow has since scaled down its military operation, a low-level insurgency has continued in the region.