Islamabad - Pakistani security forces have killed 25 militants as a roadside bomb exploded next to a tanker carrying fuel for North Atlantic Treaty Organization troops in Afghanistan, leaving one dead in Pakistan's tribal region, officials said.

Meanwhile, two people were killed in the Dera Ismail Khan district in North West Frontier Province (NWFP) as the sectarian tensions between rival Sunni and Shiite Muslim groups continued to rise a day after a suicide bomber killed 35 people at a Shiite funeral.

Helicopter gunships and artillery targeted several militant locations overnight in Bajaur tribal district, where Pakistani security forces are fighting Taliban and al-Qaeda fighters. The action that started late Friday continued on Saturday morning.

"Our forces have destroyed some important hideouts of militants and killed some 25 insurgents, including a commander Faizullah," said a security official from paramilitary troops Bajaur Scouts.

Government forces launched a security operation in Bajaur in late August to eliminate Taliban and al-Qaeda sanctuaries used to carry out cross-border raids on US-led international forces in Afghan province of Kunar.

According to the official claims, the action has so far killed hundreds of rebels, but the security forces are still struggling to gain complete control over the district.

In the neighbouring Khyber tribal region, a remote-controlled bomb planted along Pak-Afghan Highway destroyed a tanker carrying fuel supplies for NATO forces.

"One by-passer was killed and two more injured, while the driver remained unhurt," said a local official, Amirzada Khan.

NATO forces in the land-locked Afghanistan rely heavily on supplies of fuel, equipment and other items through the vital Khyber route.

According to the US State Department, up to 75 per cent of the US military supplies, including 40 per cent of the fuel for its troops stationed in Afghanistan, go through the famous Khyber Pass.

But Taliban militants have disrupted the supplies by carrying out dozens of raids along the route. More than 400 trucks and containers have been torched or plundered over the last three months.

Separately, sectarian tensions in Dera Ismail Khan district, which borders ungoverned tribal region, intensified a day after a suicide bombing at Shiite funeral procession killed 35 people and injured more than 150.

Unknown gunmen opened fire on a group of Sunni Muslims in a market, leaving two of them dead and three more injured, said a local police officer Amanullah Khan.

The shooting occurred as hundreds of military troops were deployed in the city to quell the riots that erupted after the suicide bombing on Friday.

In another incident, two suspected terrorists were killed when their explosive-laden car exploded pre-maturely in Lucky Marwat area, which is adjacent to Dera Ismail Khan.

"They were perhaps heading for Dera Ismail Khan for a terrorist attack," said a police official.

Extremists in rival Sunni and Shiite factions have carried out dozens of attacks on each other across Pakistan, further threatening to destabilize the nuclear-armed country. (dpa)