Federal Reserve Chair Janet Yellen fuelled speculation that the US will raise rates at the end of this year in her first public comments since the Fed’s meeting last week, causing Asian shares to falter and sending short-term US bond yields up.

Yellen stated that the US could be looking at a December rate “liftoff”, but that rates would rise gradually. Asian shares broke a 2 day rising streak and her comments gave a much-needed boost to the dollar.

“What the committee has been expecting is that the economy will continue to grow at a pace that is sufficient to generate further improvements in the labour market and to return inflation to our 2 percent target over the medium term,” Yellen said at a House Financial Services Committee hearing.

She added that “if the incoming information supports that expectation then our statement indicates that December would be a live possibility.”

The Bank of England is also set to announce a timescale for a rate rise today, in what has again been dubbed ‘Super Thursday’. Governor Mark Carney will present the British central bank’s latest economic forecasts.

The Bank of England cut rates to a record low of 0.5 percent in 2009 after the financial crisis.