Algerian President Abdelaziz Bouteflika, who has been plagued by ill health since suffering a stroke last year, has left a French hospital in Grenoble and flown back to his country, a French police source has told the Reuters news agency.

An ambulance escorted by several vehicles was seen leaving the private clinic in the southern city at around 1:30pm (12:30 GMT) on Saturday.

An Algerian presidential plane took off at around 2.45pm (13:45 GMT), an AFP photographer said.

Bouteflika was hospitalised at the Clinique d'Alembert clinic in Grenoble on Thursday, French police and government sources said on Friday.

A veteran of Algeria's war against France which ended with independence in 1962, Bouteflika, 77, suffered a stroke in early 2013 and was rushed to a French hospital.

He has since returned to France several times for checkups on his health.

After he was re-elected this year, Bouteflika's illness fueled speculation over a possible transition in Algeria, a key energy supplier to Europe and a partner in Washington's campaign against armed groups in the region. 

Fifteen year rule

Bouteflika joined the National Liberation Front in 1956 as the party struggled against France, the country's former colonial master, subsequently becoming Algeria's youngest minister at the age of 25. He has ruled the country since 1999.

Following last year's stroke, Bouteflika returned home looking frail in a wheelchair and was rarely seen out in public.

Despite his ailing health, Bouteflika ran for president for a fourth time, following a controversial constitutional amendment clearing the way for him to run for office indefinitely. The opposition in Algeria have refused to recognise this result.

It is widely believed that power in Algeria is concentrated in the hands of the president, who rules in an uneasy consensus with top military, Algerian state intelligence service and party officials.

Source: Agencies