The Pakistan Taliban has claimed responsibility for an attack near the Afghan border that killed at least four people.

The attack targetted a base of the Lashkar-e-Islam armed group in the valley, said political administration official Iqbal Khan on Friday.

A commander of the Pakistani Taliban, which is a rival of Lashkar-e-Islam, took credit for the attack in a call to an Associated Press reporter. The commander gave his name as Mohammed.

Both groups have been fighting for control of the Tirah Valley over the last year.

Factional fighting among the rival groups is common in parts of the border region, where tribal loyalties hold sway and the government has little or no control. Smuggling, kidnapping and drug production can earn commanders
large sums of money.

'Heavy fighting'

Elsewhere in Pakistan on Friday, fighters attacked a Pakistan army position in the volatile northwest region in a clash that left at least 33 people killed, a security official said.

The attack was the latest skirmish in a campaign in which neither side appears to be gaining an advantage.

At least 10 Pakistani soldiers and 23 fighters were killed in the clash in the remote Tirah Valley in the Bara area of Khyber, near the Afghanistan border.

"Dozens of militants attacked three recently established security checkpoints. That led to heavy fighting," a military official told the Reuters news agency.

In the Orakzai tribal region, south of Khyber, Pakistani fighter jets bombed two hideouts for fighters, killing 15 people present at the time and wounding 12, Orakzai security officials said.

Stalemate

Casualties could not be independently verified, and the fighters often dispute official accounts.
 
Several Pakistani military offensives in the tribal regions such as Khyber have failed to crush al-Qaeda groups.

The insurgency is led by the Pakistani Taliban, formally known as the Tehrik-e-Taliban Pakistan, which has an active
faction in Khyber.

The military campaign, along the entire border region and across several tribal agencies, involves more than 100,000
Pakistani troops, but it has effectively reached a stalemate in many areas.

Formed in 2007, the TTP is an umbrella organisation made up of fighters allied with the Afghan Taliban and al-Qaeda. It pledged to overthrow the Pakistani government after the military stepped up operations against fighters five years ago.
 
Khyber is one of seven ethnic Pashtun tribal regions along the porous border which have never come under the full control of the state. Fighters have taken advantage of the area's lawlessness to set up strongholds.

Khyber is one of the main land supply routes to Afghanistan for US-led NATO troops, suspended by Pakistan after a
cross-border clash in November last year that left 24 Pakistani soldiers dead.