Reports say at least 16 suspected militants were killed in the strikes.
They come days after a militant attack on Karachi airport - 39 people were killed, including the 10 attackers.
Washington agreed to suspend its drones programme in December to allow Islamabad to pursue peace talks with the Pakistani Taliban (TTP).
But pressure has been mounting on the Pakistani authorities to launch a ground offensive in North Waziristan amid a breakdown in peace talks.
The two drone strikes took place within hours of each other, striking a compound in a village near Miranshah, the main town in North Waziristan.
The first attack, carried out late on Wednesday night, is said to have killed four ethnic Uzbek militants and two Punjabi Taliban.
The second attack on Thursday morning targeted another 10 suspected militants.
On Wednesday, Uzbek militants of the Islamic Movement of Uzbekistan (IMU) claimed to have carried out the attack on the airport, saying it was in retaliation for Pakistani military air strikes last month.
The group, which is highly-trained and has bases in North Waziristan, has previously carried out large-scale co-ordinated attacks with al-Qaeda and Taliban militants in Pakistan.
Washington uses unmanned drones to carry out strikes on Taliban and al-Qaeda targets in Pakistan's border region with Afghanistan.
However, US strikes have not taken place since 25 December 2013 in response to calls by Pakistan to halt strikes and enable peace negotiations.
Pakistan carried out air strikes this week as well, saying its forces had killed at least 15 militants in the north-west Khyber region on Tuesday.
Who are the Pakistani Taliban?
•With its roots in the Afghan Taliban, the Pakistani  Tehreek-e-Taliban movement came to the fore in 2007 by unleashing a wave of violence
•Its leaders have traditionally been based in Pakistan's tribal areas but it is really a loose affiliation of militant groups, some based in areas like Punjab and even Karachi
•The various Taliban groups have different attitudes to  talks with the government - some analysts say this has led to divisions in the movement
•Collectively they are  responsible for the deaths of thousands of Pakistanis and have also co-ordinated  assaults on numerous security targets
•Two former TTP leaders,  Baitullah Mehsud and Hakimullah Mehsud, as well as many senior commanders have been killed in US drone strikes
•It is unclear if current leader Maulana Fazlullah, who comes from outside the tribal belt, is even in Pakistan, but he has a reputation for ruthlessness
Who are the Taliban?
Pakistan's 'fanatical' Uzbek militants

He said the Nord Stream pipeline would reduce Russia's dependence on Ukrainian pipelines, which were shut during gas disputes between Moscow and Kiev.
"Technical gas", needed to build up pressure, was released on Tuesday.
It is expected German consumers will begin receiving Russian gas through the new pipeline in a few weeks.
The official launch of Nord Stream will be marked with a visit by Russian President Dmitry Medvedev to Germany in November.
Nord Stream, a twin pipeline, was built at a cost of $12.5bn (Â£7.7bn; 8.8bn euros) and is 1,224km (761 miles) long, running from Vyborg in north-west Russia to Sassnitz in north-east Germany.
It should be able to move 55bn cu m of gas a year by 2013, after the completion of the second pipeline.
Mr Putin, visiting Vyborg, said Ukraine had been "taking advantage", and that relations between the two countries would now become "more civilised".
At present, 80% of Russia's gas exports to the EU flow through pipelines across Ukrainian soil.
Apart from Nord Stream, Russia has been planning another pipeline, South Stream, which will run from southern Russia to Bulgaria under the Black Sea.
The project is expected to pipe 63bn cu m of gas to central and southern Europe annually.
In another project to pipe ex-Soviet gas westwards, Turkey, Romania, Bulgaria, Hungary and Austria have agreed to construct a 3,900km pipeline called Nabucco.
It is expected to pump up to 31bn cubic metres of gas annually from the Caspian and the Middle East across Turkey and into Europe.
The US has resumed its drones programme in Pakistan, with two strikes on militant strongholds in the North Waziristan tribal region overnight.
[NEXT_CONCEPT]
Russian Prime Minister Vladimir Putin has pressed the start button to open a pipeline carrying natural gas directly to Germany under the Baltic Sea.