The European Central Bank is ready, willing and able to help put the eurozone economy back on its feet, if needed, president Mario Draghi said on Thursday.

"If warranted to achieve its objective, the governing council will act by using all instruments within its mandate. I would stress our readiness, willingness, ability to do so," Draghi told a news conference after the ECB opted to keep key interest rates unchanged at its policy meeting, despite the shock created by the British vote to quit the European Union.