Two Pakistani intelligence officials say four missiles were fired at the village of Mana Raghzai near the border with Afghanistan this morning.
At the time of the attack, suspected militants were gathered to offer condolences to the brother of a militant commander killed during an American unmanned drone attack on Saturday.
Pakistan has repeatedly asked the US to stop the drone attacks. But the US has pushed ahead with the programme, which it considers vital in its fight against al-Qa'ida and the Taliban.
It is the sixth American drone strike over the last two weeks, and emphasises the importance the US government places on the drone campaign.
Secretly, many Pakistani military commanders are believed to support the drone campaign. But among the Pakistani public, where the US is viewed with mistrust, the drone strikes are considered an affront to their sovereignty.
The Pakistani government and parliament has repeatedly asked the US to stop the drone strikes.
The ongoing attacks are also complicating efforts for the US and Pakistan to come to an agreement over reopening the supply routes to Nato and American forces in Afghanistan.
American airstrikes inadvertently killed 24 Pakistani soldiers in November, prompting Islamabad to block US and Nato supply lines into Afghanistan.
Pakistan has demanded an apology over the raid and an end to drone strikes against militants along the Afghan border as a precursor to reopening the supply lines. But the US has shown no intention to ending the attacks.