Irish celebrate as voters rejected Lisbon Treaty on the European Union reform on June 13, 2008. (Xinhua/Reuters Photo)

Germany and France, both strong supporters for the treaty, said they regret the voting result in Ireland but called on other member states to press ahead with the project.

Britain vowed to continue the ratification process of the treaty through parliament as planned, even through the country's Eurosceptics have been urging the government to hold a referendum.

Slovenia, the current holder of the EU presidency, admitted the "No vote" has "put the brakes on" EU integration but said the treaty remained a key European building block.

However, Czech President Vaclav Klaus said Friday that the treaty was finished and the ratification process must be frozen.

The repercussions of the "No" vote by the Irish have still yet to be felt across the Europe, analysts say.

Before the referendum, the Irish government led by newly elected Taoiseach Brian Cowen, major political parties and trade unions have flung their support for the Lisbon Treaty, campaigning vigorously in the past few months to get more people understand and therefore support the treaty.

The Lisbon Treaty was drafted and passed in October 2007 in the Portuguese capital by heads of state and government from all the EU member countries to reshape EU institutions and resurrect major reform proposals embodied in the failed constitution rejected by the Dutch and the French in 2005.

It envisages potentially powerful new roles for an EU president and a foreign policy chief, and reduced national veto powers in a bid to put the decision-making process onto a faster track.