ISLAMABAD - The United States should provide information about top militants in Pakistan, a government minister said on Thursday, as Washington stepped up pressure on Islamabad to go after Taliban leaders.

The United States, struggling to contain rising insurgent violence in Afghanistan, says top Islamist militants, including Afghan Taliban leader Mullah Mohammad Omar, are in Pakistan.

U.S. ally Pakistan rejects that.

They have given only apprehension that some of the Taliban like Mullah Omar and all that, they might be in Quetta, Interior Minister Rehman Malik told reporters.

The United States says an Afghan Taliban shura, or leadership council, headed by Omar is centred in the southwestern Pakistani city of Quetta.

We categorically told them that they are not in Quetta, and if they have any real-time information, they should give it to us and we will take action, Malik said.

The United States is weighing options on how to deal with the Afghan insurgency eight years after driving the Taliban from power in the weeks after the September 11, 2001, attacks.

The U.S. commander of foreign forces in Afghanistan, General Stanley McChrystal, said in an assessment leaked last week the Afghan insurgency was clearly supported from Pakistan.

Senior leaders of the major Afghan insurgent groups are based in Pakistan, linked to al Qaeda and other violent extremist groups, and are reportedly aided by some elements of Pakistan's ISI, McChrystal said, referring to Pakistan's Inter-Services Intelligence agency.

McChrystal identified the Quetta shura as the biggest threat to the U.S.-led mission in Afghanistan.

FULL COOPERATION

The Washington Post said this week U.S. officials were expressing concern over the ability of Omar and his lieutenants

to launch attacks into Afghanistan from sanctuaries around Quetta, capital of Baluchistan province.

Pakistan, battling al Qaeda-linked Pakistani Taliban militants in ethnic Pashtun lands to the north of Baluchistan, says the Quetta shura does not exist.

But many analysts say Pakistan is acting only against militants which are a threat to itself, like the Pakistani Taliban, while leaving alone those focused on fighting in Afghanistan or on targeting India.

U.S. ambassador to Pakistan Anne W. Patterson told the Washington Post this week the Quetta shura was high on Washington's list.

The deputy chief of the U.S. mission in Pakistan, Gerald Feierstein, told a group of Pakistani reporters that Omar and his command center were in Baluchistan, a news agency reported.

We have already expressed our reservations to Pakistan. Their movement is unacceptable and we expect full cooperation from the Pakistan government in this regard, the Online news agency quoted Feierstein as saying.

Feierstein also said al Qaeda chief Osama bin Laden was in Pakistan's ethnic Pashtun lands on the Afghan border, the news agency said.

The United States stepped up its attacks by pilotless drones on militants in northwestern Pakistani border sanctuaries last year as the Afghan insurgency intensified.

But Feierstein said no proposal for expanding drone strikes to Baluchistan was under consideration, Online said. He also said the ISI as an institution had no links with the Taliban but some elements were Taliban sympathisers.

(Additional reporting by Kamran Haider; Editing by Nick Macfie)

Afghanistan U.S. Pakistan