European Central Bank (ECB) chief Mario Draghi has suggested a controversial bond-buying scheme will go ahead despite opposition from Germany's Bundesbank.

Bonds with a maturity of up to three years could be purchased under the plan, he said, according to MEPs present at a closed-door meeting on Monday (3 September).

"I would expect, after this session, that there will be more bond-buying," German Green MEP Sven Giegold told journalists after the meeting.

His French centre-right colleague Jean-Paul Gauzes said Draghi had explained that "he does not have a problem with the ECB buying two-three year bonds on the secondary market, as this does not amount to printing money."

It is the first time Draghi has indicated the maturity of the bonds to be purchased. In a press conference last month, Draghi referred only to "short-term bonds" which could be bought if a country first makes an official request to the eurozone bailout fund to buy up its bonds.

Spain is issuing €3.5 billion worth of two and three-year bonds on Thursday, just hours before the monthly meeting of the ECB governing council when details are expected to be announced about the bond-buying scheme.

Even though the central bank is not allowed to directly purchase the bonds from the governments, its intention to buy them from traders (on the secondary market) may boost the demand for these bonds and lower their interest rates.

The ECB's bond-buying programme has existed since 2010. But it has been dormant this year following a massive intervention in November, which helped lower the borrowing costs of the Spanish and Italian governments.

Germany's Bundesbank is still fiercely opposing a resumption of the scheme, even if Spain promises to commit to a reform programme in return.

But some argue it has no choice.

"The ECB has taken over political responsibilities beyond the monetary policy, because politicians have not sufficiently taken up the political responsibility for the euro," Austrian Conservative MEP Othmar Karas told this website.

"The treaty is clear, the purchase of bonds that are limited in time is not a money printing machine. Limited in time means shorter than three years," he added, after also having taking part in the closed session with Draghi.

He noted that the more the ECB is forced to intervene, the less democratic scrutiny there is over these actions: "We have a clear political model, constitutional obligations, but we urgently need actions, because we have no time."

EU top rating in jeopardy

Moody's, one of the big three ratings agencies, meanwhile warned it may slash the EU's own top rating, given that Gremany, France, the UK and Netherlands could also be stripped of their AAA rating and that they account for 45 percent of the EU budget.

The European Commission is empowered to borrow up to €65 billion on behalf of the EU in the so-called European Financial Stability Mechanism.

The scheme was used for the bailouts of Ireland and Portugal, to the tune of €48.5 billion. The EU is also a guarantor for the European Investment Bank. Its potential downgrade will affect the terms under which the EIB can borrow.

Moody's warned that a "weakening of the commitment of the member states to the EU" and a relaxation of EU's budget rules could both lead to a downgrade of the EU rating as a whole.

Britain in recent months has been gripped by a political debate on whether to stay in or leave the EU, while pressure from the troubled eurozone countries is mounting on the EU commission to be less drastic on calling for reductions of budget deficits.