A special body set up to elect the Estonian president after parliament failed three times to do so also did not manage to reach a conclusive result after two attempts on Saturday.
Two rounds of secret ballots - including a run-off between former EU commissioner Siim Kallas, a member of the ruling Reform Party, and independent lawyer Allar Joks - failed to elect a president.
Parliament must now meet within the next two weeks - most likely on October 3 - to try once again to agree on a successor to Toomas Hendrik Ilves, whose second and final five-year term in office ends on October 9.
Kallas and Joks had obtained the most votes of the five considered during the first secret ballot earlier Saturday by the 335 members of the special voting body: Joks received 83 votes, while Kallas had 81.
In order to be elected president, one of the two had to achieve an absolute majority, but Kallas received only 138 of the 332 votes cast in the run-off, while Joks received 134. A total of 57 ballots were handed in blank and three were invalid.
"Personally, I am sad because I was expecting a better result today, to honestly say that," Prime Minister Taavi Roivas, also of the Reform Party, told dpa after the vote.
He said at least one opposition party had openly said they would hand in blank voting slips.
The two run-off candidates told Estonian radio that they would not stand in the next round of voting in parliament. Kallas spoke of a constitutional crisis and demanded changes to the voting system.
Commentators have also said the party squabbling had cast a shadow over the presidency and increased the public's disenchantment with politicians.
A lack of consensus among the six parties in parliament meant that three rounds of voting there in August produced no result. The parties must now put forward new candidates.
The president is a largely ceremonial role in Estonia, an EU and NATO member bordering Russia.