Citizens of Romania and Bulgaria have celebrated the start of their European Union membership with fireworks, music and dancing in the streets.

Blue and yellow EU flags were raised in the two Balkan states as they officially joined the bloc Monday after midnight.

Romanian and Bulgarian presidents and other officials greeted jubilant crowds in the central squares of Bucharest and Sofia.

EU Enlargement Commissioner Olli Rehn and representatives of member states attended today's celebrations in both countries. President of the European Commission, Jose Manuel Barroso, welcomed the new members via teleconferencing.

The accession of Romania and Bulgaria raises the EU membership to 27 and adds about 30 million people to the union.

The two countries will face continued monitoring by Brussels as they continue to combat corruption and organized crime.

The average monthly salaries in the Bulgaria and Romania are low in comparison to wages in western Europe.

The disparity has prompted several countries to impose labor restrictions against the incoming union members.

Some information for this report was provided by  AP and Reuters.