Clashes between paramilitary troops and militants left at least 38 people dead and dozens injured in Pakistan's south-western province of Balochistan, media reports said on Monday.
Fighting broke out in the Uch area of the Dera Bugti district on Saturday when security forces launched a search operation to arrest rebels, who had attacked a gas field and killed an engineer of the state-managed exploration company.
The toll rose to 38 after two days of fighting. Thirty people, including six Frontier Corps (FC) paramilitary soldiers, were killed on Sunday, the Dawn newspaper said.
There were conflicting reports about the toll as some newspapers put it at 43, with nine casualties for the FC.
"The operation has been continuing for two days against militants involved in attacks on gas installations in the Uch area," Dawn quoted an official source at saying.
The security forces also claimed to have destroyed two militant camps from where attacks were mounted on gas fields in the area.
According to Dawn, insurgents put up severe resistance to the troops. Three rebel commanders were also killed in the fighting.
A separatist group, the Baloch Republican Army, owned responsibility for the attacks on troops on Saturday, saying heavy losses were inflicted on the government forces.
Sarbaz Baloch, a spokesman for the group, claimed the paramilitary soldiers had killed and wounded innocent tribesmen, Dawn said.
Balochistan, which is Pakistan's largest but most impoverished province, has a long history of insurgency seeking greater provincial autonomy and higher share of profit on natural recourses being exploited in the area.