By Luis Jaime Acosta

BOGOTA, June 7 (Reuters) - Right-wing lawyer Abelardo De La Espriella will face left-wing candidate Ivan Cepeda on June 21 in ‌a presidential runoff in Colombia, after Cepeda on Sunday belatedly acknowledged his ‌defeat in the first round of voting.

De La Espriella of the Defenders of the Homeland movement, who ​presents himself as a political "outsider", won 43.7% of the votes, while Cepeda reached 40.9%, after the counting of all polling station ballots was completed.

Initially, Cepeda did not acknowledge the results, alleging a discrepancy in the voter registry and possible irregularities in more ‌than 800,000 identity cards, but ⁠later said he had no evidence of irregularities.

The right-wing candidate made his attendance at a televised debate conditional on Cepeda, an ally ⁠of current President Gustavo Petro, acknowledging last week's first-round results.

"In my capacity as presidential candidate for the Historic Pact and the Alliance for Life, I inform the public ​that, once ​the counting is finished, I acknowledge the ​results of the first round of ‌the presidential election," Cepeda said on his X account.

De La Espriella, nicknamed "The Tiger," has focused his campaign on security, reducing the size of the state, and boosting the economy.

The 47-year-old has promised he will be "tough on crime", tackling drug trafficking, illegal armed groups and building 10 megaprisons. He's also said he will strengthen the ‌armed forces.

Cepeda, a 63-year-old philosopher and congressman since ​2010, whose father, a communist leader, was assassinated ​in 1994 in a paramilitary attack ​in Bogota, has pledged to expand the current government's social ‌programs to reduce poverty and inequality, and ​promote dialogue with illegal ​armed groups.

Surveys have suggested Cepeda will face an even tougher contest in the second round as right-leaning voters will no longer have multiple candidates ​to choose from.

The first round ‌of voting saw a relatively low turnout of about 58%, figures from ​the country's national registry office showed.

(Reporting by Luis Jaime Acosta; Writing ​by Stefanie Eschenbacher; Editing by Kate Mayberry)