The European Union and the former communist countries that want to join the group in 2004 have welcomed a vote by Ireland endorsing the organization's eastward expansion.
A spokesman for the EU executive commission said, "We have taken a major step towards enlargement of the European Union, but there is still a lot of work to be done."
Germany, the largest EU country, praised the development, with Chancellor Gerhard Schroeder saying this decision opens the way for enlargement.
There was a similar expression from the president of the European Parliament, Patrick Cox, who is Irish. He said this is the clearest possible signal that Europe's rendezvous with history cannot be further delayed.
Meanwhile, leaders of former communist countries seeking to join the EU in 2004 praised the development.
Polish President Aleksander Kwasniewski said there is reason for joy because this shows that no internal problems can overshadow the great idea that is the expansion of the European Union.
Another leading contender for EU membership, the Czech Republic, also expressed pleasure. A spokesman for Czech President Vaclav Havel said, "The vote has fundamental importance for our future in Europe."
In neighboring Slovakia, the deputy chairman of the parliament said nothing now stands in the way of integration into the European Union.
In Hungary, meanwhile, a foreign ministry spokesman said he was pleased with the result and the Irish vote is a signal of solidarity with nations seeking to join the European Union.
But obstacles facing the 15-member organization remain substantial. The toughest issue is that of agricultural subsidies in an expanded European Union that is expected to include 10 mostly farm-intensive new members. Farm subsidies take up a large part of the EU budget.
Germany, among other countries that are net contributors to the EU budget, have called for a commitment to reforms before signing up to plans to aid the new countries. But France, which relies heavily on farm subsidies, supports the existing program and says it is too early to discuss future changes.