A man who hijacked a Turkish Airlines flight on Tuesday was unarmed, working alone and threatened to blow himself up if the pilot did not divert the flight to Italy, Italian Interior Minister Giuliano Amato said.
All 107 passengers and six crew on the Boeing 737 were unharmed in the hijack which ended with the man's arrest in Brindisi airport in southern Italy.
The 27-year-old Turk, Hakan Ekinci, has requested political asylum from Italy.
"The peculiar thing about this hijack was that it was done by a lone, unarmed man," Amato told Italy's Senate on Wednesday.
During the incident, the pilot reported there were two hijackers and the Turkish Defence Ministry said there might be four or five of them.
Checks on everyone on board after the plane had landed and Ekinci had given himself up showed he was alone.
Turkish TV initially quoted police sources saying the plane had been seized in protest at a planned visit to Turkey next month by Pope Benedict, who offended many Muslims with a speech last month linking the spread of the Islamic faith to violence.
But it emerged the hijacker was a Christian convert who wanted to avoid military service in Turkey and wrote to the Pope several months ago for help to avoid serving in "a Muslim army".
A Vatican official said the hijacking was not expected to affect the Pope's plans.
Amato said Ekinci traveled to Albania in May and requested asylum there on the grounds that he was viewed as a deserter from the Turkish army and would be punished if he went home.
Albania refused his request and he was expelled from the country on the Turkish Airlines flight from Tirana to Istanbul.
Ekinci entered the cockpit when a flight assistant left the door open soon after take-off, Amato said.
Amato said he received two versions of what Ekinci said to the pilot. He either told the pilot he would blow himself up or that he had accomplices on board who would do so if his orders were not followed.
When the pilot transmitted a code, which alerts air traffic controllers to emergency situations, Ekinci told him to insert the more specific code, which refers to a hijack.
"The pilot said he knew procedures and the meaning of codes and said he learned it all on the Internet," Amato told the Senate.
"I don't know how many of you would have known how to do that, I certainly wouldn't have."
According to passengers, 20 minutes into the flight the pilot announced that a technical failure at Istanbul airport meant the plane would have to land in Italy.
"But when we saw Italian soldiers at the airport we understood the situation. The plane was hijacked. There was no panic among the passengers," passenger Ergun Erkoseoglu told a news conference at Istanbul airport.