Latin American leaders have paid tribute to the former president of Argentina, Nestor Kirchner, who died of a heart attack yesterday at the age of 60.

Mr Kirchner, who was president from 2003 to 2007, is credited by many commentators with putting the country's economy back on its feet after a devastating financial crisis at the beginning of the decade.

He had been expected to stand for president again next year in place of his wife, Cristina Fernandez de Kirchner, who is the current head of state.

His death increases the possibility that Ms Fernandez de Kircher, who has higher approval ratings than her late husband, will seek re-election.

Tens of thousands of Argentines paid tribute to Mr Kirchner, with supporters waving the national flag and banners carrying messages of support in front of the presidential palace in Buenos Aires.

Regional leaders and political figures were due to attend a wake for Mr Kirchner at the palace today.

Opposition leaders paid tribute to Mr Kirchner's political ability but could feel emboldened by the departure of their influential foe.

Venezuelan President Hugo Chavez wrote on his Twitter account: 'What pain! What a loss for Argentina and our Americas!'

Mr Chavez has declared three days of mourning in his own country.

US President Barack Obama stressed Kirchner's 'significant role in the political life of Argentina,' while Spain's Prime Minister Jose Luis Rodriguez Zapatero expressed his 'deep shock'.