Wana, 15 Sept. (AKI) - The Pakistani army and local tribes on Monday were reported to have blocked an attempt by US troops to stage a fresh attack against militants in the region bordering Afghanistan.

Sources cited by Pakistan's Geo News, said US troops aboard two helicopters were trying to enter Pakistan near Angoor on the border when local tribes and Pakistani troops resisted the move and opened fire, forcing the helicopters to return.

Recent cross border raids by US troops have generated fierce opposition in Pakistan. The first acknowledged ground assault by US special forces based across the border in Afghanistan provoked an official complaint.

The political conflict has intensified in the past week with reports that US President George W.Bush had authorised cross-border attacks from Afghanistan in July without Pakistani agreement.

On Sunday Pakistani security forces, backed by helicopter gunships and artillery, killed 16 and wounded 25 militants in the border region.

Pakistani forces have also intensified its military offensive in the northwestern regions of Bajaur and Swat regions in the past week.

According to security officials, 64 militants were killed in the troubled Bajaur Agency at the weekend. More than 250,000 people have been displaced by ongoing conflict in the agency which is part of the Federally Administered Tribal Areas.

Army chief, General Ashfaq Kayani, last week warned the United States against violating Pakistan's borders.

At least 12 people were killed and at least 10 others injured in a suspected US missile attack in north-west Pakistan on Friday.

The US drone aircraft reportedly launched the attack near Miranshah, the main town in North Waziristan early on Friday morning.