US central bank keeps buying bonds to boost economy

US Federal Reserve has kept its $85bn-a-month bond buying in place, in an effort to keep borrowing costs low and bolster the economy.

The central bank's rate-setting Federal Open Market Committee also kept its key interest rate at zero to 0.25%.

It said unemployment remained too high for a change in its quantitative easing policy.

The US economy rebounded in the first quarter to grow by 2.5%, but was still below expectations.

The Federal Reserve uses quantitative easing, a policy of buying bonds, to increase the money supply and improve liquidity in the financial system in the hope of sparking economic growth and supporting employment.