There have been protests across Honduras over the post-election process that's left the central American country without a president-elect three weeks after the poll.
In the capital Tegucigalpa, supporters of opposition anti-corruption party leader Salvador Nasralla took to the streets with torches as the third placed Liberal Party presented a formal request to annul the results.
Nasralla, trails conservative President Juan Orlando Hernandez by 1.6 percentage points according to the widely criticized official count
The election tribunal has ten days to respond to the request for a recount or a fresh poll.
"We're asking for the result to be declared null at the presidential level, due to the scandalous fraud we have discovered," Nasralla said.
Earlier, Octavio Pineda, the secretary of the third-placed Liberal Party, presented a similar document, saying the vote should be annulled due to a violation of constitutional norms.
The Liberal Party's candidate, Luis Zelaya, has repeatedly said Nasralla won the election. Hernandez's bid for a second term, which was made possible by a 2015 Supreme Court decision on term limits, divided opinion in the coffee-exporting nation of 9 million people.
The election has been plagued with problems since voting stations closed. The tribunal declared Nasralla the leader in an announcement on the morning after the vote, with just over half of the ballot boxes counted. However, it gave no further updates for about 36 hours. Once results then started flowing again, Nasralla's lead quickly started narrowing, sparking a major outcry.
On Thursday, tribunal chief David Matamoros said there would be a re-count of 4,753 ballot boxes that arrived after the 36-hour pause, and which the opposition has claimed are tainted.