U.S. Defense Secretary Leon Panetta arrived in Cairo on Tuesday for a lightning visit to the longtime Middle East ally to reaffirm U.S. support for Egypt's democratic transition, an AFP reporter said.

The Pentagon chief is due to meet Field Marshal Hussein Tantawi, the head of the Supreme Council of the Armed Forces, or SCAF, and newly elected Islamist President Mohamed Morsi.

"In the past year, I've maintained very close contact with Field Marshal Tantawi. My message has been consistent. We strongly support an orderly, peaceful, legitimate transition to a democratic system of government," Panetta told reporters accompanying him shortly before landing in Cairo.

Panetta is visiting Cairo two weeks after US Secretary of State Hillary Clinton was in the Egyptian capital.

His trip comes amid a tense power struggle between the military, which held power after the popular uprising that toppled Hosni Mubarak, and the president, a former member of the Muslim Brotherhood.

For the first time since the ouster of the monarchy in 1952, Egypt's head of state has not emerged from military ranks.

But Panetta praised the way the then ruling military handled the elections which brought Morsi to power.

"The SCAF's show of support for a secure, free and fair presidential election last month is a critical step in this process," he said.

Panetta will also meet Morsi and "urge the Egyptian government to continue the transition to full civilian rule to provide for as broad a coalition as possible within the government."

"The Egyptian people should be proud of the progress that has been made on the road to democratic transition. I'm looking forward to meeting with President Morsi," he said.

Washington insists that the new leadership respect peace accords concluded with Israel, and has expressed concern over security problems in the Sinai peninsula.

Israel has repeatedly called on Cairo to improve security in the lawless region with which it shares a border, as does the Gaza Strip.

Panetta's Middle East tour will also take him to Israel and Jordan.

[Leon Panetta image via Agence France-Presse]