Pakistan's ISI is pushing the Taliban to attack US troops and their allies based in Afghanistan, the media here has said, close on the heels of a White House report that slammed Islamabad for not doing enough to battle terrorists holed up near the Af-Pak border.

Several similar charges against the ISI have been made in the past but “The Wall Street Journal” suggested that this one was the "strongest yet" and showed a "deteriorating relationship with an essential ally in the Afghan campaign" which had received billions of dollars in aid.

Some Taliban commanders and US officials have accused Pakistan's spy agency of telling the insurgents not to surrender, and the Americans also say they have heard similar accounts from captured militants.

"The ISI wants to arrest commanders who are not obeying (ISI) orders," a Taliban militant in Kunar province was quoted as saying by the Journal.

"The ISI wants us to kill everyone — policemen, soldiers, engineers, teachers, civilians — just to intimidate people," he said, adding that when he refused the ISI had tried to arrest him. "Afghans are all brothers; tomorrow we could be sitting together in one room."

A senior Pakistani official, however, dismissed the allegation. "Whenever anything goes wrong in Afghanistan, ISI is to be blamed," the official said. "Honestly, they see ISI agents behind every bush in Afghanistan."

Now, the ISI's motivation to keep friendly relations with the insurgents is believed to be desire to keep its leverage in Afghanistan when the US eventually leaves, as well as preventing India from getting cosy inside the war-torn country, the report said.

The newspaper further pointed out that the suspicions against the ISI are once again renewed at a time when the US is shifting focus to the militants that have found sanctuary in the lawless tribal regions of Pakistan, which border Afghanistan.

The Taliban and Haqqani network are believed to be planning and executing the majority of their attacks from the safe havens in North Waziristan and South Waziristan tribal areas.

The sanctuaries the Taliban and Haqqani have in Pakistan "is a concern we share", Gen. David Petraeus, top US commander said in Afghanistan, said recently, amid reports that the CIA is using US military resources to beef up its drones attacks inside Pakistan — a tactic many Pakistanis detest and view as violation of their sovereignty.

Despite high praise for Pakistan's fight against terrorism from the top brass, reports suggest that many US officials are frustrated at its alleged double game, which was also highlighted in the massive leak of Afghan-related documents pulled off by Wikileaks, earlier in 2010.

The newspaper said that Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, has repeatedly warned that elements within the ISI have had ties with extremist organisations and called on the intelligence agency to "strategically shift its focus".

Despite several accusations that the ISI is in cahoots with the Taliban, the US has not publicly accused Islamabad since it is not clear whether this is ISI policy or a few rogue elements are acting out.

The ISI-Taliban nexus goes back decades when the spy agency along with the CIA trained the militants to fight against the Russians in Afghanistan. Some US officials say the top levels of the ISI are committed to trying to reform the agency.

"It is difficult to know how much the lower levels of ISI answer to senior leadership," a military official was quoted as saying by the Wall Street Journal. Other officials, however, say that such activities cannot go on unless with nod from the top.

"I haven't seen evidence that the ISI is not in control of all of its parts," said a senior US defence official. A Taliban commander from the southeastern Paktia region said the ISI "is supporting those under its control with money, weapons and shelter on Pakistani soil."

Pakistan, on its part, has consistently rejected these accusations and maintains that no country has done more to fight terrorism. Earlier, a declassified White House report said that Pakistan is not doing enough to combat terrorists and extremists in its restive tribal belt where some of the most wanted insurgents are hiding.

"The Pakistan military continued to avoid military engagements that would put it in direct conflict with Afghan Taliban or Al Qaeda forces in North Waziristan," the Wall Street Journal reported citing the 27-page White House report, which is to be given to the Congress.