Outgoing US president George W Bush has delivered a message of goodwill to his successor Barack Obama. In an emotional address to the White House staff who have served him during eight years in office, Mr Bush said: "Laura and I congratulate Barack Obama and wish him and his family the very best." The president-elect will work closely with Mr Bush and the Republican administration he frequently attacked on the campaign trail as US officials try to ensure a seamless handover of power over the next ten weeks. Mr Bush said he will discuss the looming financial crisis and the Iraq war when he meets Mr Obama next week, saying the country faces economic challenges that "will not pause" to let a new president settle in. Mr Obama has until January 20 to select the senior officials who will form his administration and it is thought he has already chosen Illinois representative Rahm Emanuel to be his chief-of-staff in the White House. Mr Obama announced his transition team would be headed by John Podesta, former President Bill Clinton's last chief of staff, along with senior campaign advisor Valerie Jarrett and Pete Rouse, a top campaign aide. John Kerry, the Democrat presidential candidate who lost to Mr Bush in the 2004 election, is quietly lobbying for the role of Secretary of State. Mr Obama will take control of the Oval Office as America's first black president at a time when the nation is facing grave challenges at home and abroad. He will be under pressure to quickly name key cabinet appointments including the heads of the Treasury, State and Defence departments.