Vaclav Klaus said a decision on ratification was not on the agenda
Czech President Vaclav Klaus has said he has no intention of ratifying the EU's Lisbon Treaty for now, even though the Czech parliament has approved it.
Mr Klaus, one of the treaty's fiercest opponents, said he would wait for any new legal challenge before signing it.
He also poured scorn on senators who had changed their minds over the treaty, calling them cowardly.
The Lisbon Treaty, aimed at reforming the EU's decision-making process, must be ratified by all 27 member states.
Voters in the Republic of Ireland rejected the treaty in a referendum last year, but will most likely be asked to vote again in the autumn.
The treaty is seen by opponents as a way to impose a federalist agenda, undermining national sovereignty.
Shortly after Czech senators voted 54-20 in favour of the Lisbon Treaty on Wednesday, President Klaus appeared live on television from Prague Castle to give his response.
Mr Klaus criticised senators who he said had caved in to pressure from politicians and the media, and "turned their backs on the Czech Republic's interests".
"Our politicians have always found similar cowardly explanations: We are too small, too weak, we do not mean anything in the European context, we must fall into line, although we disagree with it," he said.
"I reject this. Either we regained sovereignty after the 1989 overthrow of the communist regime... or this was nothing but a tragic error," he continued.
The result depended on many members of the conservative Civic Democratic Party (ODS) led by outgoing Prime Minister Mirek Topolanek, putting their doubts aside and backing the plan.
LISBON TREATY PROGRESS
Approved by parliament: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, The Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, UK
Defeated by referendum: Irish Republic
Delays: Legal challenge holding up ratification in Germany, Polish and Czech presidents also resisting ratification
Mr Klaus said he would refuse to ratify the treaty, pending an attempt to have it reviewed by the Czech Constitutional Court, a process that could take several months.
"The treaty is dead for the moment because one member state rejected it in a referendum. This is why a decision on the ratification of the treaty is not on the agenda for me," he added.
The Czech Foreign Minister, Karel Schwarzenberg, told the BBC that Mr Klaus' opposition would not stop the treaty's eventual ratification.
"The president is entitled to do whatever he wishes in the framework of his constitutional rights. I do think it's lamentable, but the Lisbon Treaty isn't dead, as we proved today by ratifying it," he said.