Commission President Jose Manuel Barroso said both countries had made enough progress to join the union.

But they will be checked for progress in curbing organised crime and corruption, and ensuring food safety and the proper use of EU funds.

Bulgaria's PM said the move was the fall of the Berlin Wall for his nation.

Romanian Prime Minister Calin Tariceanu said his people should be proud of themselves, but should not make the mistake of thinking that accession would mean all the country's problems would be solved.

The conditions are tougher than those imposed on previous new members, observers say.

The BBC's Oana Lungescu in Strasbourg says they are intended both as a reassurance for EU citizens, only half of whom support further enlargement, and as a warning to Turkey and the Balkan nations still lobbying for EU membership.