Five people, including an al-Qaeda operative, were killed on Thursday in a suspected US airstrike in Pakistan's tribal area and a suicide attack in the neighboring North West Frontier Province (NWFP), officials said.

Three guided missiles hit a house in Sam area of South Waziristan tribal district, which is believed to have safe havens for al-Qaeda and Taliban militants launching cross-border attacks on US-led international forces in Afghanistan.

"One foreign fighter died in the strike while three more were injured," said a local security official. The term "foreign fighter" is used to refer to an al-Qaeda member of Arab or Central Asian origin.

The missiles were fired from drones which continued to fly in the area for more than one hour after the attack, he added.

According to the security official who spoke on condition of anonymity the house was frequently visited by the local Taliban militants as well as foreigners.

However, there were conflicting media reports on the death toll.

English language DawnNews television channel reported four were killed and five injured while Urdu-language Geo and Aaj news TVs claimed six, including some foreigners, died in the airstrike.

The attack occurred in the area that is a stronghold of the head of the Pakistan Taliban Movement, an umbrella organization of several militant groups in lawless tribal region and NWFP.

Separately, four security personnel were killed and 29 wounded in a mini-bus suicide bombing at a police station in NWFP's mountain district of Swat.

Islamist militants fired rocket-propelled grenades at the police station in Mingora, Swat's main town, shortly after midnight and before the suicide bombing, said Haroon Rashid, a local security official.

The facility, located in the centre of the city, was jointly manned by the police and the Frontier Corps paramilitary force, Rashid added.

The blast damaged the police station and several surrounding buildings, including the offices of two media organizations.

Rashid said it could not be confirmed whether any of the militants were killed in the gunfight preceding the attack.

The suicide bombing came a day after the Pakistan Army said it had killed at least eight insurgents, including two important commanders, in Swat.

Security forces targeted several militant positions in the Khwazakhela area of the district, army spokesman Major Murad Khan said late Wednesday.

Swat has been gripped by violence since October 2007 when government troops launched an offensive against thousands of supporters of the region's radical cleric, Maulana Fazlullah.

Fazlullah, who uses illegal FM radio broadcasts to instigate a so-called Islamic rebellion, had announced the introduction of a hard-line Islamic judicial system for Swat before the authorities decided to launch a full-scale military operation to clear the area of his supporters.

Swat, once used to be a tourist haven, has become a virtual war zone, and many of its towns have been placed under curfew.

The increasing violence in the country has taken a heavy toll on its economy, which has seen foreign reserves eroding quickly and the inflation rate rising to 30 year highs in recent months.

Pakistan's rupee on Thursday sank to a record low against the dollar as it traded at 82 in the inter-bank market compared with Wednesday's closing of 80.7. The value of the currency has dropped by more than 25 per cent this year.