The defeated leftwing candidate in Colombia’s presidential runoff has conceded to the far-right, Trump-admiring millionaire lawyer Abelardo de la Espriella.

Since Sunday night, the preliminary count had already pointed to a De la Espriella victory by a razor-thin margin of less than 1% of the vote.

But his opponent, senator Iván Cepeda, and the current president Gustavo Petro had initially refused to recognise the result, saying they would instead wait for the official scrutiny process.

After the official count showed a 99.997% match with the preliminary results, Cepeda called a press conference in the capital, Bogotá, and finally conceded.

“At this stage of the count, I have decided to accept the result of the process, which indicates that Abelardo de la Espriella is the new president of the republic. I do so as an act of democratic responsibility. I do so to contribute to coexistence, peace and dialogue among Colombians,” he said.

The leftwing candidate, who finished with 12.7m votes – just 250,000 fewer than De la Espriella’s 12.96m – said, however, that “accepting the electoral result does not mean renouncing the truth or remaining silent in the face of facts that we consider serious and that marked this presidential campaign”.

In a reference to Donald Trump’s posts in which he endorsed De la Espriella while describing Cepeda as a “radical left marxist”, the senator said: “We denounced the open and improper foreign interference in Colombia’s internal affairs. In particular, the interventions carried out by the government of the United States and especially those of President Donald Trump in favour of Abelardo de la Espriella’s candidacy.”

On Tuesday night, in a 4,500-word social media post, Petro announced that he would begin the transition process with the president-elect.

Petro wrote that he felt as though he were handing Simón Bolívar’s sword – the relic that belonged to the military leader of South American independence from Spain and is kept at Colombia’s presidential palace – “to a viceroy”, a reference to Trump’s backing of De la Espriella.

The president-elect has announced that Colombia would join the “Shield of the Americas”, the Trump-backed initiative bringing together far-right governments across the region, which now overwhelmingly dominate Latin America. Once De la Espriella takes office on 7 August, only four countries in the region will be governed by the left.

“Colombia will NO longer be governed by an administration that is complacent towards narco-terrorism. We will combat it as it should be fought,” wrote De La Espriella, who has pledged to resume a full-scale military offensive to defeat the country’s decades-long armed conflict.