LIMA (REUTERS) - Alberto Fujimori, Peru's former authoritarian president who was freed from a 25-year prison sentence with a humanitarian pardon last Christmas Eve, was hospitalised with heart problems on Sunday (Jan 14), his doctor told local newspaper El Comercio.

Images broadcast by television station Canal N showed Fujimori, 79, waving his hand from the inside of a truck upon arriving at the Centenario clinic in Lima together with his son Kenji.

Fujimori had previously been hospitalised from late December through Jan 5 for heart problems, including high blood pressure and arrhythmia.

"He is going to have some checks done because although he has progressed favorably these seven days, he is not totally stable. He has short periods of arrhythmia," his lead doctor, Alejandro Aguinaga, told El Comercio.

President Pedro Pablo Kuczynski cited Fujimori's health in pardoning him for convictions on human rights violations and graft charges less than halfway through a 25-year prison sentence.

Kuczynski's decision, which was widely seen as a political maneuver to avoid being ousted by Congress, triggered cabinet resignations and large protests.