Buenos Aires  - Former Argentina president Raul Alfonsin, who led his country out of an era of dictatorship, was said to be in a rapidly deteriorating condition on Tuesday following a bout of pneumonia.

Alfonsin, 82, suffers from lung cancer, but his son Ricardo Alfonsin said that he was still lucid.

He was diagnosed with pneumonia on Sunday and was being treated at his home in the Barrio Norte neighbourhood of Buenos Aires.

"We have to keep waiting to see how he reacts to the medication," Ricardo said, adding that his father had "great serenity, tranquillity and absolute consciousness about the situation he is going through."

Ricardo thanked all those who had called to inquire about his father's condition, including Argentine President Cristina Fernandez de Kircher, who telephoned him from Doha.

Alfonsin, president from 1983 to 1989, headed the first democratic government in Argentina at the end of a bloody dictatorship in which some 30,000 people are believed to have been killed by pro-government military and paramilitary forces. Most of the bodies have never been found.

After leaving office, he remained active in Argentine politics. Last year he underwent surgery for lung cancer in the United States. dpa