Clinton: Al Qaeda's top commander hiding in Pakistan

"There are several significant leaders still on the run. Zawahiri, who inherited the leadership from Bin Laden is somewhere, we believe, in Pakistan," Clinton said in a Monday speech in Kolkata, India during a state visit. 

Zawahiri was Bin Laden's second-in-command and seen as the spiritual leader of al Qaeda. He was with Bin Laden when the pair evaded capture by by U.S. forces in the Tora Bora mountains in 2001. 

The Egyptian-born cleric took control of the group after U.S. special operations forces killed Bin Laden during a daring nighttime raid on his Pakistani hideout last May. 

Clinton's assertion drew a quick rebuke from Islamabad, who in turn demanded that Washington hand over any intelligence to Pakistan on Zawahiri's whereabouts inside the country. 

“We have no information about presence of al Qaeda leader Ayman al-Zawahiri in Pakistan. If anybody has any information in this regard... it should be shared with Pakistan,” Foreign Minister Hina Rabbani Khar said on Monday, according to local news reports. 

The back and forth over Zawahiri's location comes days after American intelligence officials stopped a planned terror attack by al Qaeda's Yemen cell. 

CIA agents uncovered the plot, in which an al Qaeda suicide bomber planned to detonate explosives concealed in his underwear once the airliner crossed over into American airspace. 

The attack was intended to coincide with the first anniversary of Bin Laden’s death. 

The debate also comes as American officials are trying to persuade Pakistan to reopen key supply lines that run through the country and into Afghanistan. 

Negotiators on both sides continue to hammer out the details of the plan, which would reopen American supply lines in Pakistan for the first time since Islamabad shut them down last November.

Reopening those supply lines is a critical issue to American war planners, as U.S. and coalition forces gear up for the upcoming fighting season in eastern Afghanistan.

However, a senior U.S. official told Reuters on Saturday that both parties remain worlds apart on a pending agreement.