Pakistani intelligence officials say two missiles hit the Shawal area of North Waziristan on Sunday night when the men were crossing on foot into Pakistani territory from Afghanistan.
The officials said the men have not been identified.
North Waziristan is home to a mix of Pakistani, Afghan and al-Qaeda-linked foreign militants.
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The US drone program is a source of extreme tension between the two countries.
Washington says it needs to send drones after dangerous militants because the Pakistani government refuses to engage them militarily. Pakistan charges that the drone strikes are a violation of its sovereignty.
