Pakistani intelligence officials say a US drone has fired two missiles at a vehicle in northwest Pakistan, killing four suspected militants. The officials say the attack took place Saturday in Mohammed Khel village in the North Waziristan tribal region bordering Afghanistan. They say the identities and nationalities of the slain men was not immediately known and their agents are trying to get more details. The two officials spoke on condition of anonymity because they were not authorised to speak to reporters. The latest attack comes despite Pakistani demands to halt the missile strikes. It also comes at a time when Pakistani Foreign Minister Hina Rabbani Khar is visiting Washington to discuss a range of issues, including how to resolve differences over US drone attacks in Pakistan.