U.S. defense secretary nominee Leon Panetta says his first task at the Pentagon will be to ensure the U.S. prevails in the conflicts it is engaged in, including Iraq and Afghanistan.

Testifying Thursday at a Senate hearing on his nomination, the current head of the Central Intelligence Agency said that in Afghanistan, the U.S. must continue to degrade the Taliban, train Afghan security forces and help the government take ownership of the country.

Panetta also discussed the need to do everything possible to strengthen what he called the “complicated” U.S. relationship with Pakistan. He said it is clear that the U.S. cannot succeed in Afghanistan if it is not succeeding in neighboring Pakistan, controlling terrorist safe havens and cross-border attacks.

In Iraq, he said the U.S. must ensure that the Iraqi military and security forces are prepared to safeguard their nation so it can become a stable democracy in what he called a “very important region of the world.”

On Libya, Panetta said economic sanctions, diplomatic measures and the NATO military operation there have put “tremendous pressure” on leader Moammar Gadhafi. He said if the international community continues that pressure, there are “signs” that Mr. Gadhafi ultimately will step down. He said the Libyan leader's government has been weakened significantly, and he cited opposition gains in both the east and west.

Panetta said this is a “time of historic change” and he acknowledged that the U.S. faces a “multitude of challenges” and “dangerous enemies.” But he said there is reason to be confident. He said the CIA-led operation that killed Osama bin Laden last month has given the United States the “greatest chance” since the 2001 terrorist attacks to defeat al-Qaida, but that the U.S. must keep up the pressure.

On Iran, Panetta said there is no question that it continues to work to develop some kind of nuclear capability. He reiterated President Barack Obama's statement that the U.S. should keep all options on the table for dealing with Iran.

He also said the U.S. has to play a role in what he called the “tremendous changes” taking place across the Middle East and North Africa. He said if the U.S. does not get involved, there are other countries in that region, like Iran, that are going to try to influence what takes place. He said the U.S. cannot afford for that to happen.

If confirmed by the Senate, Panetta would take over the Pentagon at a time when President Barack Obama has called for an additional $400 billion in cuts to security spending.

Panetta acknowledged the need to make “tough decisions” to rein in the defense budget, saying the challenge will be to eliminate wasteful spending while protecting the core elements needed for the nation's defense.

The Associated Press quoted Panetta as saying in a questionnaire submitted to the Senate committee that everything in the defense budget “must be on the table ,” including possible changes to military pay and benefits.

Panetta would bring extensive budget experience to the Defense Department, having served as head of the White House budget office under President Bill Clinton, and before that, chairman of the House of Representatives' Budget Committee.

Panetta received wide praise from lawmakers from both parties, and is expected to be easily confirmed. The long-time Democrat would succeed Robert Gates, who plans to retire later this month.