At least a dozen of the al Qaeda’s top leaders remain in hiding in Pakistan, according to Congressman Mike Rogers, chairman of the powerful House Permanent Select Committee on Intelligence.

Of the twenty senior leaders in al Qaeda, at least a dozen of them we believe to be traveling around Pakistan someplace, he told reporters.

It is incredibly important for us that we maintain a relationship [with Pakistan] so that we can pursue those targets that we know are posing a threat to the United States.

The 12 men on the US government’s most wanted list include Ayman al-Zawahri, who is believed to be Osama bin Laden's second-in-command and presumed heir.

Rogers also said that US politicians will demand answers from Pakistani officials on how Osama could have lived so close to the Islamabad, the capital, as well as near a major military base, without their knowledge.

I don't want to speculate if they did or they did not. I mean, we're going to ask those questions. I think Americans have the right to know that. I would like to know what they knew, Rogers said.

But at the same time, we have to remember there are still equities that we have in Pakistan as it relates to our national security. We know there are some incredibly bad people there.

Rogers emphasized, however, that Pakistan remains an important ally of the United States and that the two nations need to maintain a cooperative relationship to find the al Qaeda fugitives.