Two suspected US drone attacks in northwest Pakistan have killed at least six suspected pro-Taliban fighters, according to intelligence and security officials.

A pilotless aircraft fired missiles at two targets in North Waziristan within an hour of each other on Wednesday, the officials said.

In the first raid, four missiles were fired at a vehicle, levelling a nearby home near Miran Shah, the main town in North Waziristan.

The second strike occurred about 50 minutes later, when three missiles were fired at another vehicle in the town of Madakhel, about 40km west of Miran Shah.

The latest attacks came a day after a US drone killed at least 11 people, said by Pakistani officials to be pro-Taliban fighters, in compounds near the village of Datta Khel, west of Miran Shah.

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The tribal North Waziristan province is a refuge for Taliban and al-Qaeda fighters, and other armed groups, from where they launch attacks both within Pakistan and neighbouring Afghanistan.

The US does not publically talk about drone strikes but such indicents occur regularly, targeting Taliban commanders in Pakistan's semi-autonomous tribal belt, which Washington calls the global headquarters of al-Qaeda.

A suspected US drone strike in Miran Shah in February killed Mohammed Haqqani, a brother of al-Qaeda-linked Sirajuddin Haqqani, whose network is fighting against US and local forces in neighbouring Afghanistan.

The drone war against Taliban leaders has focused increasingly on North Waziristan.

Taliban and al-Qaeda-linked groups are blamed for a wave of suicide and bomb attacks across Pakistan that have killed more than 3,000 people since 2007.