The strike took place about 24 km east of Miranshah, the main town in North Waziristan, known as a hotbed of Taleban and Al-Qaeda militants, they said.
"We have got confirmed reports of five dead but the number could be higher," said a Pakistani intelligence official in the region, who declined to be identified.
Another official said militants had cordoned off the area.
It was the second attack by pilotless US aircraft in the area in the past two days. Seven militants were killed in a similar strike on Saturday.
The United States, struggling to stabilize Afghanistan, stepped up its missile strikes in Pakistan's northwest after a Jordanian suicide bomber killed seven CIA employees at a US base across the border in the eastern Afghan province of Khost in December.
Most of the attacks this year have been in North Waziristan.
US ally Pakistan officially objects to the drone strikes, saying they are a violation of its sovereignty and fuel anti-US feeling, which complicates Pakistan's efforts against militancy.
