In the first attack, the drones fired four missiles at a compound being used as a militant training camp in Shawal area of North Waziristan tribal agency, officials were quoted as saying by TV news channels.
Eighteen militants were killed and the compound was destroyed in the attack. Local residents said more persons could be buried in the rubble of the compound. A drone targeted a car in the second attack, killing four militants.
Both attacks, in which several militants were also injured, occurred within minutes of each other.
The US has carried out five drone strikes in Pakistan's tribal belt this week, indicating that Washington has no plans to roll back the campaign with unmanned spy planes despite protests from Islamabad.
On Monday, at least 18 suspected militants were killed in three drone strikes in South Waziristan.
Al-Qaeda terrorist Ilyas Kashmiri was reported killed in a drone attack last week but US officials have said they have no confirmation of his death.