President Barack Obama has chosen his special envoys for the troubled Middle East and Afghanistan-Pakistan regions.

He also promised US help in ensuring a lasting truce in Gaza, which has been rocked by a 22-day Israeli offensive against Hamas that left the territory devastated.

Mr Obama chose former Senator George Mitchell as an envoy who will try to jump-start the faltering Arab-Israeli peace talks.

During his busy first week in office, Mr Obama also chose former ambassador to the United Nations Richard Holbrooke to be the first-ever special US envoy for Afghanistan, Pakistan and related issues.

Both the envoys have records of success in helping settle long-running violent conflicts - Mr Mitchell in Northern Ireland and Mr Holbrooke in the Balkans.

"We have no time to lose," said Mr Obama, who introduced the envoys at an event with newly confirmed Secretary of State Hillary Clinton.

Mr Mitchell will go to the Middle East to help ensure the durability of the ceasefire in Gaza.

"It will be the policy of my administration to actively and aggressively seek a lasting peace between Israel and the Palestinians, as well as Israel and its Arab neighbors," Mr Obama said.

Mr Obama seemed to allude to Iran when he said his administration wanted to signal to all countries in the region "that external support for terrorist organizations must stop".

The Bush administration had accused Iran of supporting the Palestinian militant group Hamas and the Lebanese guerrilla group Hezbollah, and in the past had linked Tehran to weapons and explosives smuggled to insurgents in Iraq.

Mr Obama said during the campaign he favored high-level engagement with Iran but since the election he has given no details on when that effort might start.

Pressed on Iran during a briefing, White House spokesman Robert Gibbs reiterated that Mr Obama believes: "We're going to have to engage our friends and our enemies in order to make our country safe and secure."

Mr Obama has ordered a full review of the US strategy in Afghanistan, where he has pledged to boost troop strength, and told generals to take the first steps towards a pledge to withdraw troops from Iraq.

He has pledged to shift the focus of the struggle against terrorism back onto Afghanistan and away from Iraq.

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