El Salvador's too-close-to-call presidential runoff election has raised competing claims of victory from a former fighter for leftist guerrillas and the once long-ruling conservative party that fought a civil war from 1980 to 1992.
Norman Quijano, the candidate of the conservative Nationalist Republican Alliance, or ARENA, said his party was on ''a war footing'' and vowed ''to fight with our lives, if necessary'' to defend what he claimed was his victory.
But preliminary returns from nearly all polling stations showed him a few thousands votes behind Salvador Sanchez Ceren, the leftist candidate of the now governing Farabundo Marti National Liberation Front, or FMLN.
The margin of just under 7000 votes was just over 0.2 per cent of the approximately 3 million ballots cast.
Ceren also claimed to have won.
''The men and women of El Salvador are the ones who decide, and if you don't accept the result, you are violating the will of the people,'' Ceren said.
''I say to my adversary, to his party, that my administration will welcome them with open arms, so that together we can build a new country.''
It was a surprising result, considering that opinion polls in the weeks leading up to the election had put Quijano, the former mayor of San Salvador, 10 to 18 percentage points behind Ceren.
The president of El Salvador's Supreme Electoral Tribunal, Eugenio Chicas, said the race was ''extremely tight'' and said neither candidate could claim victory.
''This tribunal orders neither party to declare itself the winner, in light of results that are so close that only the final count can decide,'' Chicas said, adding that ''the margin is so close that we ask for prudence.''
He said the final vote count would begin Monday.
Quijano alleged fraud, and called on the army to play a role, a statement that carries ominous echoes in a country where 76,000 people died in the civil war, which pitted the army against the leftist rebels.
''We are not going to allow Venezuelan-style fraud, in the style of Chavez and Maduro,'' Quijano said, referring to the late Venezuelan President Hugo Chavez and his hand-picked successor, Nicolas Maduro.
''We have our own recount, which shows we won.''
Quijano criticised the electoral tribunal, saying it ''sold out to the dictatorship,'' and said that ''the armed forces are ready to make democracy.''
The country's military leaders made no comment on the elections.
Ceren, 69, had been widely expected to easily win and become the first true guerrilla to lead this Central American nation.
Outgoing President Mauricio Funes, who won the presidency from ARENA in 2009, was a journalist who was sympathetic to the FMLN rebels during the civil war but was never a guerrilla.
Ceren campaigned on a promise to deepen the outgoing government's popular social programmes and govern as a moderate.
He said he envisioned ruling like Uruguayan President Jose Mujica, also a former guerrilla who formed an inclusive government.
Quijano, 67, accused the former guerrilla of appearing to want to lead the country like Venezuela's Chavez, and he warned of a return of communism. He also promised to crack down on rising gang violence.
Ceren was a top rebel commander who helped negotiate the 1992 peace accords that ended El Salvador's civil war, in which the United States supported the government against the FMLN to prevent communism from spreading in Latin America.