Algerian President Abdelaziz Bouteflika has been admitted to a hospital in France, according to French officials.
The elderly leader, who suffered a stroke last year, is currently being treated in Grenoble, police and government sources said.
The officials gave no further details on Mr Bouteflika's condition.
The 77-year-old, who has led Algeria since 1999, has rarely been seen in public since his re-election to a fourth term in April.
Mr Bouteflika was admitted to hospital on Thursday, French officials, speaking on condition of anonymity, told reporters.
Regional newspaper Le Dauphine Libere said that Mr Bouteflika had been admitted to the cardiology unit of a private clinic in the south-eastern French town.
The paper reported that an entire floor of the clinic had been booked out to ensure maximum security.
The Algerian government has not responded to reports of the president's hospitalisation.
However the head of his ruling FLN party said they were "not true", Reuters news agency said.
President Bouteflika is a veteran of the Algeria's war of independence from France, which ended in 1962.
He was elected president in 1999, following the country's bloody civil war in the 1990s.
His most recent election victory in 2014 was criticised by opposition parties, who said the polls were flawed and that Mr Bouteflika was unfit to run because of his health problems.
Mr Bouteflika was hospitalised in Paris in 2005 due to a stomach ulcer, sparking concerns about his health.