President Barack Obama's top economics advisor, Larry Summers, is to leave the administration at the end of the year.

 Under Mr Summers, the council has been at the heart of the government's economic policy making. The president praised him for "brilliance, experience and judgement" at "a time of great peril" for the US. But the departure of Mr Summers, who is returning to a post at Harvard University, is the latest from the White House economy team.

In July budget Director Peter Orszag stepped down and Chairwoman of the Council of Economic Advisers, Christina Romer, left earlier this month. Earlier on Tuesday, the US Federal Reserve issued a downbeat assessment of the US economy and said that its main interest rate was likely to be kept at current levels close to zero for a long time. In a statement issued after a regular policy meeting the Fed also said it was prepared to take additional measures to support the economy if needed.