ISLAMABAD - CIA Director Leon Panetta told Pakistan's army and intelligence chiefs that he was concerned about a reduction of US troops allowed in the country, but was bluntly told no American boots would be allowed on the ground, Pakistani military officials.

Panetta, nominated to take over as defence secretary next month, arrived in Pakistan on Friday in an unannounced visit, his first trip since a secret US raid that killed Osama bin Laden and severely damaged ties between the allies.

Pakistan's army said on Thursday it had drastically cut down on the number of US troops allowed in the country and set clear limits on intelligence sharing with the United States.    

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"He (Panetta) expressed concerns over the reduction of trainers and operatives. We told him very clearly 'no boots on our soil is acceptable'," said the Pakistani military official.

Panetta held talks with army chief General Ashfaq Kayani and Lieutenant General Ahmad Shuja Pasha, head of military intelligence.

The Pakistani military released a statement saying: "Both sides discussed the framework for future intelligence sharing."

A US embassy spokesman said he had no information on the talks.

The United States kept Islamabad in the dark about the May 2 raid by Navy SEALs until after it was over, humiliating Pakistan's armed forces and putting US military and intelligence ties under serious strain.

"We told him that we are clear. We don't want their people. Intelligence sharing is fine and we are ready for that," said another military official.    

Washington was angered by the fact that bin Laden had apparently been living for years in a Pakistani town about a two-hour drive from the intelligence headquarters.

Pakistan has been under mounting pressure to prove it is a more reliable partner in the America's campaigns against Islamist militants launched after the September 11 attacks on the United States.

The United States believes the nearly decade-old war effort in neighbouring Afghanistan cannot succeed unless Pakistan tackles insurgent safe havens near the border.

On Friday, Afghan President Hamid Karzai, also a US ally, arrived in Islamabad and asked Pakistan to help end the Taliban insurgency.

Pakistan, which supported the Taliban government that ruled Afghanistan from 1996 until its ouster in 2001 by US-backed forces, will be crucial to any attempts to stabilize its western neighbor.

But Pakistan has often been accused of playing a "double game," promising the United States it will go after militants, while supporting some groups such as the Haqqani network, an allegation it denies.

US commanders say the military effort in Afghanistan is being undermined partly by Pakistan-based militants.

The Haqqanis use safe havens in Pakistan's North Waziristan region to stage cross-border attacks against American troops in Afghanistan, and US officials have accused Pakistani intelligence of ties to the group. Pakistan denies the allegations.