Spanish voters have overwhelmingly endorsed the new European Union constitution in a non-binding referendum.

With more than 75 percent of the vote counted, official returns indicate more than three-quarters of participating voters said "yes" to the charter in Sunday's balloting.

Exit polls estimated turnout at about 41 percent - more than the Spanish government had predicted, but less than voted in last year's EU parliamentary election.

Prime Minister Jose Luis Rodriguez Zapatero had urged voters to go to the polls for what he called a decision of great importance to a United Europe.

Nine European states plan votes similar to the Spanish referendum, but Germany and other nations are submitting the text to their parliaments rather than to a popular vote.

Lithuania and Hungary already have approved the constitution, which must be ratified by all EU members before it can take effect.

Some information provided at AP, AFP and Reuters.