Top U.N. officials called on the international community Wednesday to act to keep crisis-torn Central African Republic from becoming a "failed state."

Speaking before the U.N. Security Council, the officials called on the body to support the African Union's efforts to restore order in the country, plagued by insecurity and humanitarian crisis.

Osama Bin Laden's successor as the leader of al-Qaida has struggled to unite its various factions, a U.N. report said Wednesday, but the group remains an evolving threat.

The report, delivered to the U.N. Security Council by a group of experts, said al-Qaida's Egyptian leader Ayman Al-Zawahiri had failed to rebuild the group's core leadership in Pakistan.

German Foreign Minister Guido Westerwelle said he hoped for progress in the dispute over Iran's nuclear program after Hassan Rowhani assumes the presidency on Saturday.

Westerwelle told German news agency DPA on Friday that Rowhani's inauguration offered an "opportunity" to clear the impasse but that "deeds not words" were what counted.

Syrian opposition leaders on Thursday pressed U.S. Secretary of State John Kerry to arm rebel groups and said there could be no peace talks while government forces kill civilians.

Kerry held his first meeting with Syrian National Coalition president Ahmad Jarba at the U.S. mission to the United Nations in New York.

President Barack Obama's nominee for U.N. envoy Wednesday slammed the global body's "unacceptable bias" against Israel, and pledged to lobby hard to get America's closest Mideast ally a seat on the Security Council.

Even as detractors criticize her past statements about Israel, genocide expert and human rights champion Samantha Power enjoys bipartisan support in the U.S. Senate, where broad cooperation this week on executive branch nominees was likely to ease her expected confirmation.

The United States on Monday led western calls for tougher U.N. action on Iran's arms supplies to Syria and its Lebanese ally Hizbullah.

The calls came as Russia blocked a U.N. panel's unanimous ruling that a ballistic missile launch by Iran was a breach of international sanctions, diplomats said.

The U.N. Security Council on Sunday condemned an ambush on U.N. and Africa Union troops in Sudan's Darfur region that killed seven peacekeepers.

A unanimous statement from all 15 members of the security council "in the strongest possible terms" condemned Saturday's attack on a patrol of troops with UNAMID -- the AU-U.N. mission in Darfur.

European Union foreign policy chief Catherine Ashton will hold talks in Brussels next week on Iran's contested nuclear drive with senior officials from six global powers, the first since Tehran elected a new president.

Ashton's spokesman Michael Mann said Ashton would meet on Tuesday with political directors from the group of nations that have been negotiating with Iran on its nuclear program.

North Korea tested a rocket engine earlier this year in a potential bid to further develop its missile capability, a U.S. think-tank said Thursday after reviewing new satellite images.

Images of the Tongchang-ri rocket base in the country's northwest indicated the North conducted at least "one or more rocket engine tests" in late March or early April, the U.S.-Korea Institute at Johns Hopkins University said.

Russia on Thursday blocked a U.N. Security Council demand that Syria allow immediate access to thousands of civilians trapped by a government offensive on the city of Homs, diplomats said.

Diplomats said Russia's opposition to the statement proposed by council members Australia and Luxembourg was a new sign of a growing international split over the 26-month old conflict.