PESHAWAR: Clashes between outlawed militant groups in the northwestern Pakistan escalated late Tuesday as Tehrik-i-Taliban Pakistan (TTP) militants set ablaze houses of at least 10 civilians, accusing them of being supporters of the rival Ansarul Islam (AI) group.

Locals and the eyewitnesses confirmed the burning of the houses in Khyber Agency’s restive Tirah Valley, while other reports say at least 20 militants from both sides have also died in fresh clashes.

Meanwhile, sources say hundreds of tribal families have fled to Afghanistan owing to excessive artillery shelling by Pakistani security forces and aerial bombing in parts of the valley.

Officials confirmed that fresh clashes have escalated in Maidan area of Tirrah Valley though they were uncertain about the exact number of casualties.

Ansarul Islam spokesman Sadaat Afridi claimed the group has lost four fighters while three others were injured in the ensuing gun-battles still continuing in the flashpoint valley.

“We have killed more than 13 TTP fighters as their attack on the civilian houses was repulsed in Maidan Bar bagh area,” he said.

Sadaat claimed the rival TTP militants had started targeting the civilian population after losing ground in the battles, and has so far set ablaze  more than 10 houses.

Speaking about targeting of civilians, Ehsanullah Ehsan, a spokesman for the TTP, said the people were supporters of the Ansarul Islam.

“They have taken up arms against the Taliban, so they would be dealt with similarly,” he added.