Cameroon's 91-year-old president, Paul Biya, returned to the country on Monday after a 42-day absence that had sparked questions about his health and whereabouts.

The chartered plane carrying the president and his wife Chantal Biya from Geneva landed at Nsimalen International Airport in the capital Yaounde a few minutes before 5 p.m. (1600 GMT).

Biya was received on the tarmac by his secretary general Ferdinand Ngoh Ngoh, with whom he chatted briefly before getting into his car.

The nonagenarian head of state did not speak to the public. But as his motorcade exited the airport, Biya waved at supporters through the back window of his car.

Biya's prolonged absence fuelled widespread speculation he was unwell, prompting authorities to put out statements saying the president was in good health.

Cameroon later outlawed any discussion about his health, saying it was a matter of national security.

Thousands of supporters of the ruling Cameroon People's Democratic Movement (CPDM) party lined the 22-km stretch (13 miles) from the airport to the Etoudi presidential palace, clad in fabrics bearing Biya's image.

Onlookers also turned out onto the streets to confirm for themselves that the head of state was still alive.

Besides billboards with messages welcoming the president back home and wishing him well, supporters also carried banners, one of which read: "Long life to His Excellency Paul Biya, father of the nation."