According to the US version of events, Obama took French President Nicolas Sarkozy aside to suggest a formulation for compromise language on tax havens in the final communique.

Obama then took the Chinese delegation, led by President Hu Jintao into a corner of the plenary session room and received agreement on the language, before bringing the two sides together to seal the deal, the official said.

"He called over Mr Sarkozy with translators and sherpas in tow and reached agreement, there was a shaking of hands. The resolution was that the G20 would take note that the OECD had published today a list," the official said.