Washington, Feb 26 (IANS) Pakistan may be cracking down on the Afghan Taliban partly as a response to building US pressure following revelations from the arrest of Pakistani-American David Headley, according to a US South Asia expert.

A US court in Chicago has charged Headley with scouting targets for Pakistan based terror outfit Lashkar-e-Taiba (LeT) for the November 2008 Mumbai terror attacks.

Along with Headley, Pakistan born Canadian terror suspect Tahawwur Hussein Rana, has also been charged with providing material support to LeT for the Mumbai attacks.

'After months of mounting frustration with Pakistan over its unwillingness to crack down on Afghan Taliban leaders finding sanctuary on its soil, Pakistan appears to be coming through with cooperation that could help turn the tide in the war in Afghanistan,' said Lisa Curtis, a senior research fellow for South Asia at The Heritage Foundation.

'The Afghan Taliban leadership based in Pakistan coordinates the insurgency across the border in southern Afghanistan and thus convincing Pakistan to disrupt their sanctuary is critical to coalition forces gaining the upper hand against the insurgents,' she said.

'It is unclear why Pakistan is stepping up to the plate now on cracking down on the Afghan Taliban,' Curtis said. 'Most observers believe Islamabad may be seeking to ensure it has a role in determining any potential settlement of the conflict.'

'Others say it is partly a response to building US pressure,' she said noting 'President Obama appealed directly to the Pakistanis to crack down on the Afghan Taliban through a letter hand-delivered by National Security Advisor Gen. (James) Jones to Pakistani President (Asif Ali) Zardari last fall.'

'The letter coincided with revelations from the arrest of David Headley, a Pakistani-American who worked with the Lashkar-e-Taiba in Pakistan, to scout sites for the November 2008 attacks in Mumbai,' Curtis noted.

Headley was arrested by US authorities in early October and a former Pakistani Army major was named in the US affidavit as serving as Headley's handler for the Mumbai terror attacks.

'Since then, the US has repeatedly made the case to Pakistan that facilitating some terrorist groups while fighting others is counterproductive,' Curtis said suggesting, 'It is possible this message is finally beginning to sink in.'

'But given Pakistan's long track record of support to militant groups fighting in Afghanistan and India, it is too early to determine whether the most recent arrests signal a permanent reversal of its past policies, or merely a tactical shift to demonstrate its leverage in the region,' she said.