Daniel Martinez, the candidate for Uruguay's leftist Broad Front governing coalition, said the election had a festive atmosphere. (Photo: AFP)

MONTEVIDEO, Nov. 28 (Xinhua) -- Uruguayan presidential candidate Daniel Martinez of the ruling progressive Broad Front conceded defeat on Thursday and acknowledged the victory of the opposition candidate Luis Lacalle Pou of the conservative National Party in Sunday's presidential runoff.

As the official counting of the ballots entered the final stretch, Martinez said via Twitter that "the continued tabulation of votes is not changing the trend. Therefore we greet president-elect @LuisLacallePou, with whom I will have a meeting tomorrow."

Martinez also expressed "a heartfelt thank you to those who placed their trust in us with their vote."

Preliminary results reported late Sunday by Uruguay's Electoral Court showed Lacalle Pou leading with 48.7 percent of the votes compared to 47.5 percent for Martinez.

Given the thin margin, the court announced it would launch a careful count this week, with official results set to be released on Friday.

Lacalle Pou also took to Twitter on Thursday to express his "acknowledgment and appreciation to all the men and women who these days have been defending the vote and democracy at each (ballot counting) table. My thoughts are with you."

The National Party has called for celebrations in Montevideo on Friday to mark its victory, the party's first since 1989.