Pakistani intelligence officials say a US missile strike has killed at least four alleged fighters near the town of Ghulam Khan in the North Waziristan tribal agency.
"It was an American drone attack. Four militants have been killed - the death toll may rise," a security official in Miranshah, North Waziristan's main town, told the AFP news agency.
Another security official in Peshawar confirmed the attack and death toll, but the AP news agency has quoted security officials as putting the toll at eight.
Officials in Miranshah and Peshawar say the fighters killed in the strike were associated with the al- Qaeda-linked Haqqani network, but they are still seeking more information on this.
They said the fighters were moving from one area to another when their vehicle was struck by missiles from an unmanned US aircraft.
Ghulam Khan is known to be controlled by fighters from an armed group headed by Maulvi Gul Bahadur, and is located 15km northwest of Miranshah, the main town in North Waziristan.
It is the third day this week that missile attacks have targeted the North Waziristan tribal area.
Thirty-five suspected fighters were killed in missile attacks on Monday and Tuesday, officials said.
More than 100 such missile strikes have been launched this year, more than double last year's total.
Nearly all have targeted locations in North Waziristan.
Source: Al Jazeera and agencies