Polish election tight - exit poll
A sombre election season in Poland was prolonged by two weeks when a first round of voting produced no immediate successor to Lech Kaczynski, the president killed more than two months ago in a plane crash.
Results show the interim president and parliamentary speaker, Bronislaw Komorowski, is leading Kaczynski's identical twin, Jaroslaw Kaczynski.
But Mr Komorowski appeared to fall short of the 50% needed for outright victory.
The two leaders must now go head-to-head in a runoff vote on July 4, without eight other candidates who ran on Sunday.
Mr Kaczynski, 61, addressing supporters, made a rare reference to the plane crash that killed his brother, noting that the campaign has been anything but normal.
He said "it's an election which is the result of a huge catastrophe, a huge misfortune, a huge tragedy".
An exit poll by Millward Brown SMG/KRC showed Komorowski with 45.7% of the vote and Mr Kaczynski with 33.2%. A second poll, by OBOP, showed 41.2% for Mr Komorowski and 35.8% for Mr Kaczynski.
But as partial official results were reported several hours later, it appeared that Mr Komorowski's lead was narrower than it originally seemed.
Based on 71% of voting stations reporting, Mr Komorowski had 40.1% of the votes and Mr Kaczynski had 37.4%, the State Electoral Commission said.
Mr Komorowski, 58, told his supporters at a campaign night party in Warsaw that he felt "happy and fulfilled" knowing he has the "support and the trust of millions of voters in Poland.