Fresh clashes broke out Friday between riot police and opposition supporters in Honduras, as the counting of votes in a cliff-hanging presidential election rolled into a fifth day. Police said at least two officers and 12 civilians were injured, some by gunfire, after violence erupted in several parts of the country -- sparked by opposition candidate Salvador Nasralla claiming fraud and calling his supporters onto the streets. Thousands of Nasralla supporters across the country blocked roads -- with viral footage of confrontations with police, who attempted to disperse demonstrators with tear gas, circulating on social media. Meanwhile, in the capital Tegucigalpa, protesters lit bonfires of sticks and tires on boulevards and on exit routes out of the city. The unrest sparked panic, with people rushing to supermarkets and gas stations to stock up after stores were closed on Thursday. "Yesterday (Thursday) we were closed because of the protests, and today when we opened the store was full of people," an employee at Tegucigalpa's La Colonia supermarket. In a statement police announced the arrest of 50 people participating in looting between Thursday and Friday. President Juan Orlando Hernandez -- seeking re-election despite a constitutional ban on a second term -- held a 1.5 percentage point lead over his leftist rival, TV personality Nasralla, with 94 percent of the vote counted, the Supreme Election Tribunal (TSE) said. Security forces said rioters had damaged vehicles and businesses, some of which had been doused in gasoline and set on fire. One opposition leader, Juan Barahona, said the protests would continue -- despite the violence appearing to subside on Friday. "Day and night we are going to go out into the streets, because only then will the theft of the presidency be reversed," he said. Hernandez broadcast a statement calling for calm and telling his supporters to wait for the result later Friday. "By the way we are going, we are going to do very well," he said. He also called on his supporters to not react to the violence, and instead "act by setting an example, as citizens with dignity, citizens with maturity who respect others." The TSE said Friday it was carrying out a special count -- with officials from both camps present -- to review ballots with inconsistencies, blurs and other errors which must be counted before a result can be declared. The Organization of American States observer mission urged the authority in a letter Thursday to ensure that 100 percent of the ballots were processed before declaring a result. "Political parties should be given the opportunity to present challenges. These will have to be dealt with impartially and within a reasonable time frame and following due process," it said. "This is the only way to restore confidence in this election and in the integrity of the popular will."