The Federal Reserve and the European Central Bank may mop up as much as 90% of the money they pumped into banks over the last decade now that high inflation and interest rates make that extra liquidity unnecessary, a paper by a Fed economist showed on Thursday.

U.S. Treasury Secretary Janet Yellen said on Thursday the World Bank should add disaster clauses to debt agreements with poorer countries, speaking ahead of a summit in Paris that will discuss how to boost crisis financing for low-income nations.

Oil prices were little changed in early trading on Friday but were headed for a 3% drop for the week on worries about the outlook for fuel demand after a bigger-than-expected interest rate hike in the UK and warnings about looming U.S. rate hikes.

The dollar drew support from a bout of risk aversion on Friday as hawkish comments from global central banks, including the Federal Reserve, stoked fears that their aggressive monetary tightening could push economies into a deeper downturn.

Bank of Japan (BOJ) board member Asahi Noguchi said on Thursday the central bank must maintain ultra-loose monetary policy to ensure wages, seen as key to driving inflation to its 2% target, continue to increase as a trend.

Euro zone inflation is stubborn and may require a protracted period of high interest rates to contain, partly due to an exceptionally tight labour market, the European Central Banks' (ECB) two German policymakers said on Wednesday.