The United States expressed concern Saturday over deadly violence between Israel and Palestinians across the Gaza border and urged both sides to restore calm.

"We are deeply concerned by the renewal of violence in southern Israel," said State Department spokeswoman Victoria Nuland in a statement. "We call on both sides to make every effort to restore calm."

Five Taliban Guantanamo detainees have agreed to be transferred to Qatar, and Kabul has dropped its opposition to the move as it seeks to boost peace efforts, an Afghan government spokesman said Sunday.

The inmates told a visiting Afghan delegation they were willing to be transferred to the Middle East state, and it was now up to the U.S. whether they were freed, said Aimal Faizi, spokesman for Afghan President Hamid Karzai.

A top U.S. intelligence official had talks in Algiers Saturday ahead of a regional security conference, the official APS news agency reported.

Under Secretary of Defense for Intelligence Michael Vickers discussed the security situation and U.S.-Algerian cooperation in the fight against terrorism and organized crime with Interior Minister Daho Ould Kablia, it said, quoting a ministry statement.

President Barack Obama Friday called Russia's president-elect Vladimir Putin to congratulate him on his election win, despite earlier U.S. concern over reported vote irregularities.

The call inaugurated a relationship that will decide the fate of "reset" U.S. relations with the Kremlin which the White House sees as a key foreign policy achievement headed into Obama's reelection campaign.

Taliban militants armed with guns and rockets ambushed a Pakistani military convoy Friday, killing seven soldiers in the militant stronghold of North Waziristan, officials said.

The attack took place at Khar Qamar, 30 kilometers west of Miranshah, the main town in the district that has become the most notorious Taliban and al-Qaida stronghold on Pakistan's border with Afghanistan.

Saudi Crown Prince Nayef bin Abdul Aziz, the kingdom's veteran internal security czar, arrived in the U.S. city of Cleveland on Friday for scheduled medical tests, the royal palace announced in Riyadh.

"The crown prince, (who is also) deputy prime minister and interior minister, arrived in Cleveland from Morocco for medical examinations that had been previously scheduled," the palace said in a brief statement carried by the official SPA news agency.

A deal on the transfer of the controversial U.S.-run Bagram prison and other detention facilities to Afghan authorities is expected to be signed later on Friday, an official said.

"There is expected to be a signing of a memorandum of understanding to transfer U.S. detention facilities to Afghan control," a Western official told Agence France Presse on condition of anonymity.

U.S. President Barack Obama and his Afghan counterpart Hamid Karzai agreed in a video conference Thursday to continue a "partnership" tested by violence sparked after U.S. troops burned Korans.

"President Karzai updated the president on the security situation in Afghanistan, which has calmed since the events of recent weeks," said White House spokesman Jay Carney.

World powers said Thursday that mooted upcoming talks with Iran focused on its nuclear program must be "serious", without pre-conditions and produce "concrete results."

"We call on Iran to enter, without pre-conditions, into a sustained process of serious dialogue, which will produce concrete results," said a statement on behalf of the United States, China, Russia, France, Britain and Germany, known as the P5+1.

Iran's supreme leader Ayatollah Ali Khamenei on Thursday welcomed comments by U.S. President Barack Obama damping down talk of war against Tehran over its controversial nuclear drive.

"This talk is good talk and shows an exit from illusion," Khamenei's website quoted the leader as telling clerics from the Assembly of Experts, the 86-member body which selects the supreme leader, supervises his activities and can dismiss him.