BRUSSELS: Eurozone leaders are ready to increase the firepower of its bailout fund "several fold" but will not give a headline figure, said an EU source familiar with a draft agreement to be adopted at a summit on Wednesday.

Eurozone leaders were meeting in Brussels to find ways to beef up the 440-billion-euro European Financial Stability Facility (EFSF) without actually increasing the individual guarantees provided by governments.

But the lack of any precise figure could unnerve markets already concerned that the EFSF is not big enough to rescue a big economy, such as Italy, after Greece, Ireland and Portugal were bailed out.

Germany and France agreed to increase the fund "at least" fourfold, according to a diplomatic source.

Germany leans towards a formula that would increase the fund's firepower to at least one trillion euros.

Belgian Prime Minister Yves Leterme also called for it to be increased "a notch over one trillion euros," adding: "It is crucial that (the summit) succeed before markets open tomorrow."

But another source said "there will not be any figures" published at the summit.