Western leaders were scrambling to put together a rescue deal for Ukraine yesterday, as the EU’s top economic official warned that financial aid was imperative to save the country from bankruptcy.

“It will have to be measured in billions rather than hundreds of millions,” Olli Rehn, the EU’s economic commissioner, said on the sidelines of a meeting of G20 finance ministers and central bank governors in Sydney.

Intense discussions between the EU and its US allies suggested no bailout would be agreed without a new government willing to commit to reform. “There are economic reforms that we all know have to be started, at least, in order for the international community to help,” warned Christine Lagarde, IMF managing director, after the G20 meeting.