QUETTA: An armed clash between two separatist groups left at least 20 militants dead in Balochistan's Kohlu and Dera Bugti districts late Monday night.

The local administration, however, could not verify the number of casualties.

"Yes people have been killed, but we are not sure about the number of casualties", a levies official told Dawn.com via telephone.

The clash took place in Pir Suri Darbar and Han Nullah, the two areas located at the border between Dera Bugti and Kohlu districts of the restive province.

Both sides used heavy weapons against each other for a long time.

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A security official who declined to be named since he was not authorised to speak to media told Dawn.com that all the dead militants belonged to two Baloch separatist groups.

Several militants were also injured during the exchange of fire, he said.

The situation in the area remained tense owing to the clash and people remained confined to their homes as result of firing.

Dera Bugti and Kohlu districts are considered to be the most sensitive districts of Balochistan. Militants in the area have been targeting vital national installations and security forces in the area for the past several years.