MOSCOW, November 15 (RIA Novosti) - Unknown assailants attacked a police checkpoint in the Russian North Caucasus republic of Ingushetia, and tried to blow up a police motorcade, investigators said Sunday.

"At about 4:45 Moscow time unknown assailants used automatic weapons and grenade launchers to fire on a police checkpoint in the Arshty village. No one was injured," the Investigation Committee said on the incident that took place in the Sunzha District near the border with Chechnya.

The committee said that after a police motorcade headed to the crime scene, an explosive device planted on the roadside detonated.

"The device's power was equivalent to about 5 kg of TNT. A crater 4 meters in diameter and over 1.5 m deep formed as a result of the explosion," the committee said.

An investigation is underway.

Attacks on troops, police and other officials have been reported almost daily in Ingushetia and Russia's other North Caucasus republics in recent months.

On August 17, Ingushetia was rocked by a suicide bombing which killed at least 20 people and injured 260 people. In June, Ingush President Yunus-Bek Yevkurov survived a car bomb attack on his motorcade.