Former Peruvian President Alberto Fujimori, who has been serving a prison term for crimes against humanity committed during his presidency, was rushed to hospital on Sunday for the second time in a month, prison authorities announced.

The 83-year-old, who has already served 15 years of a 25-year prison sentence, suffered a drop in blood pressure and irregular heartbeat and was urgently transported to hospital, where his condition was stabilised, the National Penitentiary Institute said on Twitter.

He was later transferred to a medical clinic for continued monitoring.

Undergoing heart surgery in October, Fujimori suffers recurrent respiratory, neurological and hypertension problems and was hospitalised on March 3 after suffering strong arrhythmia. After an 11-day stay in hospital, he was returned to the police base where he is the only prisoner.

Fujimori’s latest health scare comes a week after the Inter-American Court of Human Rights (IACHR) urged Peru to refrain from implementing a high court ruling that would have freed Fujimori under a 2017 presidential pardon.

Lima has said it would abide by any IACHR decision.

Fujimori, who was president from 1990 to 2000, was subsequently jailed over massacres committed by army death squads in 1991 and 1992 during which 25 people were killed in supposed anti-terrorist operations.