A US drone has fired missiles at a suspected Taliban training camp in northwest Pakistan, killing six people, intelligence officials have said, in the third such strike in as many days.

Three missiles from the unmanned aircraft hit the camp in the Shawal area of South Waziristan just after midday on Tuesday, two intelligence officials told the Reuters news agency.

Nine suspected rebels were also reported injured, they said.

The US halted drone strikes for the first six months of 2014 while the government engaged in ultimately fruitless peace talks with the Taliban.

But the strikes restarted in June, just days before Pakistan's military announced an anti-Taliban offensive, and their pace has stepped up this month.

Five suspected rebels were killed in a strike in Shawal on Monday, and another five killed in a strike in the same area on Sunday.

The Shawal valley is a thickly forested, mountainous area where many of the rebels who fled the anti-Taliban offensive are believed to be hiding.

Pakistan's government routinely publicly protests against the strikes as an infringement of its national sovereignty but has often given the green light to them in private. 

Source: Agencies