President Obama plans to name CIA Director Leon Panetta as the next secretary of defense. As part of a broad reshuffling of his defense and intelligence teams, the president is also expected to pick Gen. David Petraeus, the U.S. commander in charge in Afghanistan, to take Panetta’s place at the helm of the CIA.

The changes are part of a series of top nominations expected to be announced as early as Wednesday.

Officials say Obama is expected to announce that Lt. Gen. John Allen would replace Petraeus as Afghanistan commander, and that diplomat Ryan Crocker will be the next U.S. ambassador in Afghanistan. A senior defense official also told Fox News the president will “almost certainly” tap Gen. James Cartwright to be chairman of the Joint Chiefs of Staff. Cartwright is currently vice chairman.

The changes would probably take effect this summer. Gates has already said he will leave this year, and Petraeus was likewise expected to leave his post as Afghanistan commander.

The moves come as the United States faces a changing landscape in the Middle East and surrounding region. U.S. forces continue to work alongside NATO allies to keep Libyan leader Muammar al-Qaddafi at bay. As the Obama administration determines how to handle the unrest in other countries, including Syria, the defense team is meanwhile trying to complete the drawdown in Iraq and make more measurable progress in Afghanistan — a task made more difficult by souring relations on the other side of the border with Pakistan.

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