A roadside bomb has exploded near a convoy of border troops in a breakaway region of southern Russia.

The bomb went off Monday, in the main city of Ingushetia, Nazran, located in Russia's restive North Caucasus region.

Russian authorities said the Ingush Interior Ministry has sent investigators to the scene to assess the damage and determine the number of casualties.

Separately, Russian authorities say two policemen and at least one gunman were killed in Dagestan, another troubled North Caucasus republic. The deaths came during a security operation near the Dagestan-Chechnya border.

Russia blames Islamist extremists in Chechnya for inciting rebellion among non-Russian ethnic groups in the northern Caucasus.

Some information for this report was provided by AP.