Gunmen in the volatile southern region of Dagestan shot and killed three police officers, in the latest violent episode to rock the Caucasus. The incident occurred on Monday afternoon in the regional capital Makhachkala, as traffic police attempted to stop a car driven by the assailants.

Two of the gunmen were killed in the shoot out, according to government sources. Other gunmen were able to flee the scene in another car and evade capture, state media reported.

Videos posted to social media show several bodies lying on the street beside a police vehicle, as more gun shots can be heard.

A number of injured people were rushed to hospital for treatment, where at least one died.

The injured included two gunmen and two police officers and several civilians - among them a 17-year-old girl.

Authorities later announced they had opened a criminal investigation into the incident, amid fears that the gunmen could be part of an ISIS cell.

Dagestan, a Muslim country, has suffered several lethal attacks in recent years, resulting in a number of brutal killings.

Security services shot and killed four militants connected to the Islamic State in March.

Authorities claimed the militants were plotting to attack a regional branch of the interior ministry.

Over the years, ISIS has developed a growing presence in the North Caucasus, particularly in Dagestan.

Abdurashid Magomedov, Dagestan's interior minister, has previously claimed that there are over one thousand ISIS members in the republic.

In one brutal terror attack, ISIS militants killed five people and left five others wounded in Kizlyar.

The southern Russian republic has become increasingly unstable in recent years, with tensions also growing with its neighbour Chechnya over disputed land.

Last June, the country was rocked by a major terror attack, when gunmen attacked police posts, churches and a synagogue in Makhachkala and Derbent.

At least 20 people were killed as well as five gunmen. Around 46 others were injured and taken to hospital.