Algerian President Abdelaziz Bouteflika is being treated at the Geneva University Hospitals (HUG), where he has been held since Sunday, the Tribune de Geneve newspaper reported on Wednesday, citing what AFP said were "multiple and well-informed sources."
The president's office earlier announced his plans to travel to the European country for "routine medical checks."
According to Swiss media, the octogenarian president has received medical care in Switzerland since the 1980s.
In 2002, Bouteflika presided over the end of the Algerian civil war between the government a coalition of Islamist militants. In recent years, terrorist groups have reportedly resumed their activities, waging low-intensity warfare against Algerian defence forces.
Algerians are set to go to the polls on 18 April. The opposition remains split despite earlier efforts to field a single candidate to challenge Bouteflika.