A cycling trip through Central Asia turned into a nightmare when a hit-and-run driver turned his car around and killed four western tourists in an incident that’s being treated as a terrorist attack.

The tourists, two from the US, and others from Switzerland and the Netherlands, were killed on Sunday as they were cycling through a rural area 90 kilometres south-east of the capital Dushanbe.

Three others, from Switzerland, the Netherlands and France, were injured. One of them also had a stab wound.

Tajikistan’s Interior Minister said police had tracked down the car involved in the attack.

Ramazon Rakhimzoda said: ''During active search operations, the car that ran into the group of tourists was found. A chase ensued after the suspects as they went on the run. One of them was detained, one was liquidated and three are on the run. All measures to detain them are being taken."

Thousands of people from Central Asia have joined Islamic State militants in recent years. Several men from the mainly Muslim region have been involved in attacks in the West.