The strike was carried out in Datta Khel area in North Waziristan district, a known bastion of Taliban and Al Qaeda fighters involved in cross-border raids on NATO-led international forces in Afghanistan.
"Three Arabs and an Afghan national are among the seven killed," an intelligence official said on condition of anonymity.A second official who also sought anonymity said that "at least three more people are injured and it is not immediately clear if any high value target is among those killed and wounded".
It was the third US drone strike in the last 24 hours in North Waziristan. On Wednesday six alleged militants died in two US missile attacks.
The US military has stepped up attacks in North Waziristan, carrying out around 30 drone attacks in the last two months.
Washington does not publicly acknowledge the drone attacks but US authorities have claimed unofficially that the strikes have eliminated dozens of suspected Al Qaeda operatives.Pakistan has protested the attacks, but it is widely believed that state intelligence agencies coordinate with the US to identify potential targets.