Treaty changes to achieve even closer European integration will "probably" be necessary to cope with the economic crisis, European Commission President Jose Manuel Barroso has said.
After talks with German Chancellor Angela Merkel in Brussels at the Commission, he said the EU was putting in place a raft of economic plans which should reassure markets, including stronger eurozone regulation and supervision, a quadrupling to 440 billion euro of an existing bailout fund and a tax on bank transactions.
But more might need to be done and it might require treaty change, he said - something Mrs Merkel said last month was necessary to get the EU out of the debt crisis.
Mr Barroso said: "We may need treaty change for more integration if current (financial) mechanisms are proved not to be enough."
He said the idea was not a delaying tactic, adding: "We are not proposing to have treaty change to avoid decisions we have to take now, so it cannot be a way of postponing that.
"But yes, probably in the future we may have to have treaty change, and it is a good indication for so-called markets and investors that we are looking for forward integration in the euro area, and not less Europe."
The remarks came hours after Foreign Secretary William Hague warned Conservative eurosceptics of a long wait if they thought treaty change could be a chance to negotiate the return of powers from Brussels.
Chancellor Merkel said the question was "how do we wish to shape the Europe of the future?".
She went on: "Member states have transferred some powers to Europe and the commission uses those powers and this is European reality - we wish to act together for the benefit of all our citizens and we should support the union, especially at a difficult time like this."
On the Greek crisis she said Greece had to remain part of the euro area and be given the chance to "improve its situation".