Prime Minister David Cameron has clashed with French President Nicolas Sarkozy over the UK's involvement in discussions about the eurozone crisis, BBC reported.
Mr Sarkozy believes the final talks on Wednesday should be limited to nations which actually use the euro.
Mr Cameron said all EU leaders should be present to debate issues which could affect them in one way or another.
The clash came on the day when leaders agreed to change the Union's treaty if necessary to help resolve the crisis.
EU president Herman Van Rompuy said after a day of emergency talks in Brussels that members would "explore the possibility of limited change".
Mr Cameron said he had sought assurances to protect the UK's interest if there is change.
All EU leaders are now set to attend the final meeting on Wednesday, which was originally meant to be attended by only the 17 countries that use the euro.
That prompted French leader Mr Sarkozy to speak out. He said he was sick of reading in newspapers about advice Mr Cameron and his Chancellor George Osborne were offering the eurozone.
At one point in the exchanges, Mr Sarkozy was quoted as telling Mr Cameron: "We are sick of you criticising us and telling us what to do."
On Sunday morning the leaders of all the European Union's 27 members held talks about the Greek debt crisis, recapitalising banks, and bolstering the bailout fund.
This was followed in the afternoon by a separate meeting of the 17 nations that use the euro.
Speaking after the meeting, Mr Van Rompuy said that altering the treaty was under discussion. Although no proposed details were given, any change is likely to involve closer fiscal and economic cooperation.
"The aim is deepening our economic convergence and strengthening economic discipline," Mr Van Rompuy said.
He said the words "limited change" meant "not a general overhaul of the institutional architecture".
He added: We also said that we would need the agreement of all the 27 (member states) before we can decide on a treaty change."
David Cameron clashes with France's Sarkozy over euro
Prime Minister David Cameron has clashed with French President Nicolas Sarkozy over the UK's involvement in discussions about the eurozone crisis.
