The party whose candidate trailed the front-runner by less than 2 points in Panama's presidential election on Sunday, called for counting all the votes before a winner is announced in the Central American country.
The narrow race raised the possibility of an upset by Romulo Roux, 54, of the centre-right Democratic Change (DC) party, who lagged in pre-election polls behind Laurentino Nito Cortizo by more than 10 points.
With 90% of votes counted, Cortizo had nearly 33% of the tally, compared with about 31% for Roux, in the single-round presidential vote in one of the world's fastest-growing economies.
This is very close. Let's be responsible and not go forward and announce anything before we count everything, and count it well, the Democratic Change party posted on Twitter.
Cortizo, a 66-year-old former agriculture minister from the moderate left Democratic Revolution Party (PRD), aimed to woo the country's 2.8 million voters with promises to fight graft following bribery scandals and the canal nation's role in hiding the wealth of global elites.
The former businessman also promised to clamp down on corruption after allegations of embezzlement of public funds in Panama, whose trans-oceanic canal handles some US$270 billion of cargo each year.
Shortly before casting his vote, Cortizo said he feared for Panama's reputation as a major financial hub and the impending verdict of the Financial Action Task Force (FATF), which evaluates countries by their measures to combat money laundering.
We are worried about it and we will do everything we have to do to prevent money laundering ... We want a robust financial system, Cortizo said.
Panama previously appeared on FATF's list of countries deemed deficient in their measures to tackle money laundering. Earlier this year, Panama passed a law that makes tax evasion illegal.
Panama's image was tarnished by a corruption scandal involving Odebrecht and the Panama Papers leak of 11.5 million documents from Panamanian law firm Mossack Fonseca that detailed how the world's rich evade tax through offshore centers.
Cortizo also said he would continue to deepen ties with China, but has suggested he might move more slowly than President Juan Carlos Varela, who angered the United States by signing several major infrastructure projects with Beijing.
Roux offered a constitutional reform to strengthen the independence of the judicial branch. He is also calling for Panama to restore its image to attract investment.