At least 45 people have died in a missile strike by a US drone aircraft in Pakistan, officials there have said.

    The people killed in South Waziristan region had been attending a funeral for others killed in a US drone strike earlier on Tuesday.

    Intelligence officials said at least 45 people had been killed and dozens more injured in the later strike, when two missiles were fired.

    But a local official told BBC News the death toll was more than 50.

    The region is a stronghold of Pakistani Taliban leader Baitullah Mehsud.

    Also on Tuesday, tribal leader Qari Zainuddin, who often criticised Mehsud, was shot dead by a gunman in north-western Pakistan.

    Earlier this month, Zainuddin criticised Mehsud after an attack on a mosque, which killed 33 people.

    The Pakistani army is preparing to launch an offensive against Taliban fighters under Mehsud's command, who are blamed for a number of deadly attacks.

    But Zainuddin's killing is being seen as a setback for the government in its efforts to isolate Mehsud ahead of the security forces' next phase of their anti-Taliban offensive in the tribal areas bordering Afghanistan, says the BBC's Mike Wooldridge in Islamabad.