US President Barack Obama has named his two key envoys - to the Middle East, and Pakistan and Afghanistan. George Mitchell, who negotiated an end to Northern Ireland's Troubles, has been charged with moving forward the Middle East peace process. Richard Holbrooke has been named envoy to Afghanistan and Pakistan. He brokered the 1995 deal that ended the war in the former Yugoslavia. Earlier, Mr Obama ordered Guantanamo Bay prison camp to close within a year. 'New management' All overseas CIA detention centres for terror suspects are to close as well, Mr Obama ordered. He also signed executive orders for a review of military trials for terror suspects and a ban on harsh interrogation methods that critics have said amount to torture. With Thursday's announcements, Mr Obama has signalled that American diplomacy is under new management, says the BBC's Kevin Connolly in Washington. Newly-appointed Secretary of State Hillary Clinton described the Middle East and Afghanistan-Pakistan as the two most pressing foreign policy issues confronting the US. "We have no time to lose," said Mr Obama after Mrs Clinton introduced the new envoys. Mr Mitchell would head to the Middle East as soon as possible to shore up the fragile truce between Israel and Hamas in Gaza. Israel must re-open the border crossing into the Gaza Strip "to allow the flow of aid and commerce," Mr Obama said. "Hamas must end its rocket fire... The United States and our partners will support a credible anti-smuggling and interdiction regime so that Hamas cannot re-arm," he added. But Hamas spokesman Osama Hamdan told al-Jazeera television that Mr Obama would fail in the Middle East unless he changed his position. Israel ended a three-week offensive on Sunday, pounding the Gaza Strip with bombs and shells and sending in tanks and infantry in an attempt to stop Palestinian militants firing rockets into southern Israel. 'Central front' Richard Holbrooke, a former ambassador to the UN and the architect of the Dayton Accord that ended the war in the Balkans, is to co-ordinate US policy in Afghanistan and Pakistan. Mr Obama said there was a "deteriorating situation in Afghanistan and Pakistan" and that the region is now "the central front" in the battle against extremism. Earlier, as signed orders to set in motion the closure of the Guantanamo Bay prison, Mr Obama said the US would continue to fight terror, but would maintain American values while doing so. "The United States intends to prosecute the ongoing struggle against violence and terrorism," he said. "We are going to do so vigilantly, we are going to do so effectively, and we are going to do so in a manner that is consistent with our values and our ideals." Mr Obama has repeatedly promised to close the Guantanamo Bay prison, where some 250 inmates accused of having links to terrorism remain and 21 cases are pending. Many of the detainees have been there for years and have never been charged. Correspondents say closing the prison will not be easy. Questions remain over where those charged will be tried and where those freed can be safely sent. Secret CIA prisons around the world are also to be closed, although the time frame for this is unclear. The secret rendition - or transfer - of terror suspects to these prisons was widely criticised after they came to light in the wake of the invasion of Iraq in 2003. Mr Obama also banned the use of threats, coercion, physical abuse and waterboarding in the interrogation of suspects - all techniques that had been permitted under the Bush administration. Source: BBC