Two days of urgent talks by E.U. foreign ministers in Brussels have failed to bridge the major gaps blocking agreement on a constitution for the 25-nation group.

British Foreign Secretary Jack Straw clashed with his counterparts from France and Germany, in particular, as they argued over issues such as voting procedures and human rights.

The British government faces strong skepticism in parliament over the new E.U. constitution, and has promised to put the document to a public referendum. Officials say to get the constitution approved they must secure veto power for all members on any new E.U. rules related to taxation, foreign and defense policy, and social security.

Britain also asked for an amendment in the document's Charter of Fundamental Rights. It wants to ensure that the charter does not end up creating new social and employment rights under European Union law.

With agreement still elusive, France urged Ireland, which holds the E.U. rotating presidency, to issue a final draft. Ireland has called another meeting of the foreign ministers for the beginning of next week.

The goal is to settle on a constitution by the next E.U. summit in mid-June.

The E.U. members failed to make their last deadline for agreement in December, and they are under pressure to agree by their new self-imposed deadline next month. Experts say the organization needs the document in order to be able to operate efficiently, having just increased its membership from 15 to 25 at the beginning of this month.

If Britain or any other country fails to ratify the constitution, it is to be set aside. Some in Britain are concerned that if that happens due to a British 'No' vote, other members will draft a new document that would, in effect, give Britain second-class status in the organization.

Irish Foreign Minister Brian Cowen says he remains confident an agreement can be reached. But the British foreign secretary says the wording must be right, and he warns that next month's summit could come and go without its key constitutional centerpiece.