Polls opened Sunday morning in Croatia's presidential election, with surveys showing an opposition candidate is leading the race.

A dozen candidates were seeking to replace incumbent President Stjepan Mesic, who has served his maximum two five-year terms.

A runoff is likely as polls show none of the candidates appears close to getting the 50 percent support needed for an outright victory.

Ivo Josipovic, a law expert and classical music composer backed by the largest opposition Social Democratic Party, appears to be ahead with 30 percent support in polls.

The presidential vote is the fifth since Croatia claimed independence from the former Yugoslavia in 1991. More than half of Croatia's 4.4 million inhabitants registered for the polls.