Washington, Sept 16 : The US has increase strikes in Pakistan’s tribal areas after being convinced over the past six years that the Pakistan Army was neither able nor willing to fight the Taliban and Al Qaeda and because some in its intelligence agency were sympathetic towards the extremists.

Washington, Sept 16: The Pentagon has refuted yesterday’s media reports that US-led coalition helicopters based in Afghanistan were fired at in Pakistan and forced to turn back.

“The incident did not happen,” The News quoted Pentagon spokesman Bryan Whitman as saying.

Media report had yesterday suggested that the incident occurred at the Angoor Adda tribal area.

Whitman added that after studying the facts a statement by a Pakistani security official “didn't appear to be accurate.”

Earlier, there were conflicting reports that shots were fired when US-led coalition helicopters based in Afghanistan neared the border with Pakistan.

Islamabad - Pakistani security forces and armed tribesmen on Monday foiled an attempt by US troops to enter Pakistani territory by firing shots at them, security officials said.

The attacks came as Pakistani forces killed up to 20 Taliban militants in the tribal region bordering Afghanistan.

Two US military helicopters crossed into Pakistan and tried to land near Angor Adda area of South Waziristan tribal district along the Afghan border before dawn, a local security official said.

New Delhi - India's Defence Minister AK Antony on Monday suggested that neighbouring Pakistan may have backed the militants responsible for multiple bombings in New Delhi over the weekend that killed 24 people.

Nearly a 100 people were injured when five bombs exploded in crowded market and commercial areas in New Delhi on Saturday evening.

"Militants are getting support from across the border and it's a fact," Antony told reporters in New Delhi responding to a question about possible Pakistani involvement in the blasts.

Islamabad  - Pakistani security forces and armed tribesmen on Monday foiled an attempt by US troops to enter Pakistani territory by firing shots at them, security officials said.

Two US military helicopters crossed into Pakistan and tried to land near Angor Adda area of South Waziristan tribal district along the Afghan border before dawn, a local security official said.

"But our security forces and the tribesmen who were alert opened fire at them and forced them to flee back to Afghanistan," added the official who spoke on condition of anonymity.

Islamabad  - Afghan authorities on Monday handed over the son of a Pakistani scientist allegedly linked to al-Qaeda held in US custody to Pakistan's embassy in Kabul, officials said.

Aafia Siddiqui, 36, a US-educated neuroscientist, has been charged in a Manhattan court with assault on and attempted murder of her US investigators. She was arrested in Afghanistan's Ghazni province on July 17.