London, Mar. 31 US President Barack Obama said the destruction of militant safe havens in Pakistan's tribal areas could not be achieved without full cooperation from the army and the intelligence, but how far can the US push the Pakistan envelope, asks a BBC analyst.

Recently, three American generals have recently accused elements in Pakistan's ISI of supporting Taliban and Al Qaeda. The unprecedented attack, he points out, follows the announcement of a new US strategy for Afghanistan.

Charges against the ISI may not be new, but they have never before been made so publicly.

To ensure Pakistan's support in fighting terror on its border along with Afghanistan, the Obama administration has offered an increase in civilian aid, only with a warning that no 'blank cheque' is available for the military if it does not 'perform'.

Last year, Washington's suspicions were so strong that it scaled down intelligence sharing with the ISI, especially after accusing it of involvement in the bombing of the Indian embassy in Kabul.

As far as the Islamabad is concerned, it never gave up the idea that in order to defend itself against India, it needs a pro-Pakistan government in Afghanistan.

However, the government in Kabul is full of factions hostile to Islamabad and closely allied with India, and India is expanding its influence in the country, according to the BBC analysis.

This is all the more troubling because Afghanistan has never recognized its boundary with Pakistan.

The Taliban, therefore, can be an asset for the ISI.

"The concept of pressuring Pakistan is flawed. No state can be successfully pressured into acts it considers suicidal," Ahmed Rashid and Barnett Rubin were quoted by BBC, as saying.

America's leverage is thus limited: in pushing too much, it may lose even the limited cooperation it has, the BBC analyst concludes. (ANI)