Many of the votes cast in the presidential and parliamentary elections in El Salvador must be recounted due to technical issues, the president of the Supreme Electoral Court said on Monday.
Incumbent President Nayib Bukele already claimed victory on Sunday night and looked set to become the first Salvadoran president in almost a century to win a second term.
With 70% of the votes counted, Bukele, 42, had a comfortable lead with 83% by Monday morning. But since then, the electoral authority's electronic system has stopped updating, meaning that almost 30% of ballot boxes will have to be double-checked.
In the simultaneous parliamentary elections, the problems were even more serious, with only 5% of the votes counted before problems such as a duplication of votes when uploading data began to emerge.
In addition to the presidency, Bukele had also claimed victory for his conservative Nuevas Ideas (New Ideas) party which he said had won at least 58 of the El Salvador parliament's 60 seats.
Opposition parties in the leftist BPR block have described the elections as a "farce" and rejected Bukele's self-proclamation of himself as winner.
"The BPR condemns the unconstitutional re-election of Nayib Bukele," the block said in a statement, accusing the ruling party of "illegally modifying the electoral system and violating legal provisions within the electoral framework."
Eduardo Escobar, director of campaign group Citizen Action, told the Spanish news agency EFE that there were "irregularities."
"Without a doubt there is an irregularity that the Court has to explain," he said. "It will have to be solved so that there are no doubts about the electoral result."
Bukele is known for his crackdown on crime and his authoritarian approach. He is credited with restoring peace in a country previously plagued by gang violence, but he has done so by imprisoning over 1% of El Salvador's total population.
El Salvador's constitution actually prohibits the direct re-election of the president. However, constitutional judges loyal to the government allowed Bukule to run again. To circumvent the ban, the head of state only has to take a leave of absence for six months, until the day of the planned inauguration on June 1.
