The man is said to have forcibly entered the plane's cockpit

An airline spokesman said the man had tried to hijack the plane, but reports quoting security officials said he had not tried to divert the aircraft.

The man had been talking incoherently, harassing passengers and arguing with the cabin crew, Reuters reported.

The man was arrested at Cairo airport, and the flight continued to Doha.

The aircraft was travelling from Casablanca in Morocco to Doha, via the Libyan capital, Tripoli.

'Unarmed and incomprehensible'

The man, 30-year-old Hamad Fahd Jassem, had argued with the flight crew about getting an upgrade from economy to business class, Reuters news agency said.

He then forced his way into the cockpit and began making "incomprehensible" remarks into the pilot's microphone, alarming the passengers.

Qatar Airways spokesman, Salam al-Shawa, said the man was planning to hijack the aircraft to Geneva, Switzerland.

Nehad Gamaleddin, a doctor who spoke to Mr Jassem in Cairo, quoted him as saying he experienced a choking sensation and uncontrollable movements after the plane took off from Tripoli.

Mr Jassem is reported to have told police he had asked the airline's crew for medical help, which he said they had refused.

He is not thought to have been carrying any weapons.

A Qatar Airways official said another Kuwaiti national travelling with the man had also been detained in Egypt.