We accept the mandate of the people and congratulate the Liberal ticket

Daniel Ortega

With results from 5% of polling stations already declared, Liberal presidential candidate Enrique Bolanos leads Mr Ortega with 53% to 45% of the votes.

Final results are not expected until around 1330 local time (1930 GMT).

A larger than expected turnout had forced polling stations to stay open late into the night and delayed the announcement of preliminary results.

Daniel Ortega ruled for 10 years

On election day, few problems or irregularities were reported despite earlier fears of trouble.

Soldiers and police were out in force on the streets of the capital Managua throughout the weekend, and polling stations were under heavy guard to prevent any abuses.

European observers described the election process as slow, but careful and calm.

Final opinion polls before the vote showed a gap of less than 1% separating Mr Ortega of the Sandinista National Liberation Front (FSLN) - the former revolutionary leader and president - and Mr Bolanos, candidate of the ruling Liberal Constitutionalist Party (PLC).

The BBC's Nick Miles in Managua says that for many Nicaraguans the two candidates' past is an irrelevance - voters are most concerned about who can rescue the country from poverty.

Sandinista rule

Mr Ortega led the revolutionary FSLN government from 1979 to 1990.

The Sandinistas tried to introduce revolutionary reforms in land ownership, economic and social policies.

Parties and presidential candidates

Liberal Constitutionalist Party (PLC): Presidential candidate Enrique Bolanos Sandinista National Liberation Front (FSLN): Presidential candidate Daniel Ortega Conservative Party (PC): Presidential candidate Alberto Saborio

But they faced armed opposition from "contra" forces financed in part by the United States, and gradually lost the support of the Nicaraguan population.

When Mr Ortega stood as candidate in presidential elections in 1990 he was defeated, and the Sandinistas were swept from power.

Mr Bolanos, who was briefly imprisoned and had his assets seized when the FSLN came to power in 1979, was Mr Aleman's vice-president until he resigned to run for the presidency.

Business leaders anxious

Mr Ortega has now dropped his left-wing rhetoric, claiming to want to promote reconciliation and moderate social reform.

Business leaders in Nicaragua fear a victory by Mr Ortega could lead to an outflow of capital and investment, while Washington admits to "serious reservations" that a Sandinista victory could change the strategic balance of power in Central America.

The two men are old adversaries

However, many Nicaraguans criticise the 70-year old Mr Bolanos for failing to fight corruption while he was in the Aleman administration.

President Aleman's government has been dogged by persistent accusations of corruption, and it has been unable to reduce chronic problems such as unemployment, now estimated to affect more than half the working population.

There have also been acute food shortages in many parts of the country, caused by widespread crop failures in the wake of severe drought and flooding.