Palestinian militants pitched a protest camp Wednesday on the site of a contested Jewish settlement, in an act of defiance as US President Barack Obama began an historic visit.

International Criminal Court officials are travelling to Rwanda to collect Congolese warlord Bosco Ntaganda, who is holed up in the US embassy there, a top American diplomat said Wednesday.

Syria's regime and rebels on Wednesday called for international investigations into an attack a day earlier in which each side accuses the other of having used chemical weapons.

Central African rebels said Wednesday they would resume fighting after a deadline given to the government to meet their demands under a peace deal expired.

The first observers are preparing to monitor a demilitarised buffer zone between Sudan and South Sudan, Khartoum's defence minister said on Wednesday, a move which aims to curb cross-border rebel support.

"Peace must come to the Holy Land," Barack Obama said Wednesday as he landed in Israel for the first time as US president in a bid to ease tensions with his hosts and to frame policy on Syria and Iran.

Chinese President Xi Jinping told his South Korean counterpart on Wednesday that Beijing is willing to help reconciliation between South and North Korea, the foreign ministry said.

Barack Obama landed in Israel on Wednesday for the first time as US president, on a mission to ease past tensions with his hosts but facing scepticism about his plans to thwart Iran's nuclear threat.

Barack Obama headed to Israel on Wednesday for the first time as US president, on a mission to ease past tensions with his hosts but facing scepticism about his plans to thwart Iran's nuclear threat.

Chinese President Xi Jinping told his South Korean counterpart that Beijing is willing to help "reconciliation" between Seoul and Pyongyang, the foreign ministry said.

The US and UN were attempting to verify claims and counterclaims by Syrian troops and insurgents that chemical weapons were used for the first time in the two-year conflict.

Pope Francis has donned the symbols of papal power, vowing to embrace the "poorest" at a grand inauguration in the Vatican as leader of a troubled Roman Catholic Church.

Speculation intensified Wednesday that Australian Prime Minister Julia Gillard could be toppled by her party within days, with one report saying ex-leader Kevin Rudd was five votes from victory.

North Korea on Wednesday condemned training flights by nuclear-capable US B-52 bombers over the Korean peninsula as an "unpardonable provocation" and threatened military action if they continue.

President Ma Ying-jeou of Taiwan met with Pope Francis in St Peter's Basilica on Tuesday in a first taste for the new pontiff of a long-running dispute that pits the island against its giant neighbour China.

Troops and insurgents Tuesday accused each other of using chemical weapons for the first time in Syria's two-year conflict, as the newly elected rebel premier ruled out dialogue with the regime.

The United States said Tuesday it had seen "no evidence" that Syrian rebels have used chemical weapons and warned it would be "totally unacceptable" for the regime in Damascus to use such arms.

The United States and United Nations on Tuesday warned Afghanistan that ensuring a credible presidential election next year would be "critical" to maintaining international support after 2014.

US Secretary of State John Kerry arrived in Israel Tuesday and was expected to attend some meetings a day ahead of President Barack Obama's milestone visit, US officials said.

A group of key countries on Tuesday pressed Morocco and Western Sahara rebels not to block efforts by a United Nations envoy to renew peace talks between the two.