Washington/Islamabad/New Delhi, May 4 (IANS): Two days after Osama bin Laden's dramatic killing deep inside Pakistan, the US described its ties with Islamabad as "complicated" and said it will take a "hard look" at the assistance being given to its long time ally. Washington also pressed Islamabad to do more to bring the terrorists who attacked Mumbai to book.

Much to the dicomfiture of Islamabad, CIA chief Leon Panetta said bluntly that Pakistan was not included in the mission to kill Osama bin Laden as US officials feared it could have undermined the operation by leaking word to its targets.

Months before the launch of the mission Friday, the US had considered expanding the assault to include coordination with other countries, notably Pakistan, he told Time magazine.

But the CIA ruled out participating with Pakistan early on because "it was decided that any effort to work with the Pakistanis could jeopardise the mission. They might alert the targets," Panetta said.

The US also considered running a high-altitude bombing raid from B-2 bombers or launching a "direct shot" with cruise missiles but ruled out those options because of the possibility of "too much collateral," Panetta said.

The direct-shot option was still on the table as late as last Thursday as the CIA and then the White House grappled with how much risk to take on the mission. Waiting for more intelligence also remained a possibility.

White House Press Secretary Jay Carney told the media in Washington that US ties with Pakistan was "a complicated but important relationship".

"Pakistan is a partner - a key partner - in the fight against Al Qaeda and terrorism.

"It's a complicated relationship. There's no question. And we do have our differences.

The killing of Osama at a mansion in Abbottabad city, close to a Pakistani military academy, has caused irritants in Pakistan-US ties.

In India, US envoy Timothy J. Roemer Wednesday said: "We are certainly going to see Capitol Hill take a very hard look at the assistance that we give, and we invest in security for Pakistan and quite frankly for India. India has a vested interest in a more prosperous Pakistan."

Saying Pakistan needs to do more against terrorists, Roemer said it has to be seen whether Islamabad is using the funds given by the US in a "proper way".

"Congress is going to engage in I think two very fundamentally important tasks in the weeks ahead. One will be as we share or sell certain military equipment to Pakistan, is that being used in the proper way to take on counter terrorism efforts.

"We have seen over the past 18 months Pakistan has stepped up those efforts to target Al Qaeda leadership and degrade the leadership. Are they doing enough on Lashkar-e-Taiba? Are they doing enough on Mumbai trials? Are they doing enough on Hafiz Saeed and (Zakiur Rehman) Lakhvi? No, they need to do more," he said.

He said Pakistan needs to show results on the Mumbai trials.

"Senior level visitors from the US going to Islamabad have made very clear that Pakistan needs to do more. They need to show progress and results on the Mumbai trials. That Mumbai attack on 26/11 killed scores of Indians, six Americans, and the US wants to see progress and results and justice."

Roemer also said Osama's discovery in Pakistan would also be taken up.

"The second part of this will be in respect to bin Laden being discovered outside of Islamabad.

"Congress will ask tough questions and go to the bottom. How do we more effectively use that aid, I am sure Pakistan is helping us not only degrade Al Qaeda, but go after groups like Lashkar-e-Taiba," he said.

In Pakistan, Muttahida Qaumi Movement (MQM) chief Altaf Hussain demanded an apology from the Pakistan government and intelligence agencies for their lapse on the incident.

Dawn, a leading Pakistani daily, said Wednesday that the fact that Osama bin Laden was living right under the "military's nose" added to the way in which he was killed were matters of deep shame.

An editorial in the Dawn said: "Right under our military`s nose was found Osama bin Laden, the most wanted man of the decade, living in relative comfort in a compound with stringent security that somehow went unnoticed.

"Nor was this man simply an enemy of other countries; he and his ideology have exacted a stunning death toll in Pakistan over the last few years. Add to this the way he was killed, and embarrassment turns into deep shame."

Counter-terrorism expert Stephen Tankel said that while LeT is unlikely to replace Al Qaeda at the forefront of global jihad, it has the capability to threaten the US.

Al Qaeda leader Osama bin Laden's death has badly weakened the terror group and deprived Islamic extremists of their most visible leader, but even with his death LeT is unlikely to take its place, Stephen Tankel told the House Homeland Security Committee Tuesday.

The US should push Pakistan to provide intelligence regarding LeT's international networks and begin taking steps to dismantle LeT's training apparatus in the Federally Administered Tribal Areas, he said.

The expert's statement came on a day when it reportedly emerged that another anti-India terror group Hizbul Mujahideen owned the Abbottabad compound where Osama bin Laden was killed.

The report in the respected Globe and Mail Tuesday said that Hizbul Mujahideen was using the compound in Abbottabad where Osama lived, adding that the terrorist mastermind was sheltered by one of the militant groups that has enjoys backing from the Pakistani military.

"The place belonged to Hizbul Mujahideen. But the authorities have asked us not to share any information about the exact ownership," a police officer was quoted as saying.

The report added that Hizbul's links to Al-Qaeda would "deepen Pakistan's embarrassment" over Osama's death.