The left-wing candidate in Colombia’s presidential run-off, Iván Cepeda, has conceded defeat three days after a record number of Colombians cast their vote.

Preliminary results released hours after the polls closed showed Cepeda had been beaten by less than a percentage point by his rival, right-wing businessman Abelardo de la Espriella.

Cepeda originally said he would wait for the legally binding final count – which is still under way – but on Wednesday announced he had “decided to accept the result”.

He criticised US President Donald Trump for his endorsement of de la Espriella.

“We denounce the open and undue foreign interference in Colombia’s internal affairs, in particular the interventions of President Donald Trump,” he told journalists.

Trump had praised de la Espriella following his win in the first round of the election and labelled Cepeda a “radical Left Marxist”.

After de la Espriella beat Cepeda in the run-off, Trump said he had won “easily”, even though his 0.96-percentage-point lead was the narrowest win in recent Colombian history for a presidential candidate.

Referring to the deep polarisation in the country, Cepeda said he had decided to concede “as an act of democratic responsibility; I do so to contribute to co-existence, to peace, and to dialogue among Colombians”.

As the second-placed candidate he is entitled to a seat in the Senate, where he said he would exercise “a democratic, vigilant and constructive opposition”.

Abelardo de la Espriella, who during the campaign had threatened to “gut the Left”, also struck a conciliatory note during his victory speech, saying that those who thought differently from him would have nothing to fear.

Since Sunday’s run-off de la Espriella has already established closer ties to the Trump administration than the outgoing president, Gustavo Petro, who had repeatedly clashed with his US counterpart.

Colombia’s president-elect said on Tuesday that he would accept an invitation for his country to join the “Shield of the Americas”, a US-led alliance of Western Hemisphere countries created to combat criminal cartels and drug-trafficking.

De la Espriella will be sworn in on 7 August.