A suspicious device that forced an Air France plane en route from Mauritius to Paris to make an emergency landing in Mombasa was a false alarm, the airline’s chief executive officer has said.

Flight AF463, with 459 passengers and 14 crew members on board, had left Mauritius at 9pm local time (1700 GMT) on Saturday and was due to arrive in Paris Charles de Gaulle at 5.50am (0450 GMT).

After the suspicious device was discovered, the plane landed at Moi international airport in Mombasa before 1am.

The Air France chief executive, Frédéric Gagey, told a news conference a decision was made to land at the closest airport able to handle a Boeing 777 aircraft after a passenger found the object in the toilets.

“All the information available to us at the moment indicates that the object was not capable of creating an explosion or damaging a plane, but was rather a mixture of cardboard, sheets of paper and a timer,” he said. “It was a false alarm.”

He added that those on board were evacuated via the emergency slides. Gagey congratulated the crew for their cool-headed reaction to divert the plane. He said a safety check had been carried out in the toilets before the flight and denied any security failure.

A Kenyan police official, speaking on condition of anonymity, said the device looked like a cardboard box with a stopwatch taped to it. He said six passengers were being questioned in relation to it, including the man who raised the alarm.

Facebook Twitter Pinterest Passengers who were on board an Air France Boeing 777 aircraft that made an emergency landing are seen on a bus as they are escorted to hotels from Moi international airport in Mombasa. Photograph: Joseph Okanga/Reuters

An Air France spokesman said the passengers on the aborted flight were all being accommodated in a nearby hotel and they would depart from Mombasa at 6pm on Sunday on a new aircraft dispatched from Paris, arriving in the capital at 7am on Monday.

The Kenyan Airport Authority had posted a statement on Facebook on Sunday morning in which it described the suspect package as a bomb that “has been taken to safe destination for detonation in the morning”, but later deleted the post and replaced it as one referring only to a “suspicious object”.

A Kenyan police spokesman, Charles Owino, said of flight AF463: “It requested an emergency landing after a device suspected to be a bomb was discovered in the lavatory. An emergency was prepared and it landed safely and all passengers evacuated. Bomb experts from the navy and the CID were called in and took the device.”

The plane was still in Mombasa airport early on Sunday morning, he added.

A passenger who identified himself as Benoit Lucchini, from Paris, told journalists: “The plane just went down slowly, slowly, slowly, so we just realised probably something was wrong. The personnel of Air France were just great, they were just wonderful. So they keep everybody calm. We did not know what was happening. So we secured the seatbelt to land in Mombasa because we thought it was a technical problem but actually it was not a technical problem. It was something in the toilet, something wrong in the toilet, it could be a bomb.”

Steven Ciaran, 30 an Irishman working on Réunion island, said he had been sitting at the back of the plane watching a film when he noticed the rushed movement of cabin crew preparing emergency drills. They told him it was a technical problem and created a calm environment among the passengers, he said.

“I was very distressed because I could see we were far from the destination,” said Ciaran. “I thought the plane had difficulty and not that it had anything to do with terrorism.”

Scheduled flights to Mombasa were initially disrupted but normal operations later resumed.

Flight AF463 is the third Air France plane to be diverted in recent weeks. Two flights from the US to Paris were diverted on 18 November after bomb threats were received but no bombs were found. France has been in a state of emergency since the 13 November attacks in Paris that left 130 people dead and hundreds wounded.

Islamic State extremists claimed responsibility for the attacks in Paris as well as for the 31 October crash of a Russian passenger plane in the Sinai desert that killed all 224 people on board. Moscow says the crash was caused by a bomb on the plane and has demanded that Egypt increase security at all its airports.

