Turkish commandos killed a lone hijacker, believed to be a Kurdish militant, in a pre-dawn operation on Saturday to rescue more than 20 passengers and crew held hostage for 12 hours on a high-speed ferry near Istanbul.
The decision was taken at 3.30am Irish time to carry out a joint security forces operation, Istanbul Governor Huseyin Avni Mutlu told reporters, while the ferry lay anchored a few kilometers off shore, some 50 km west of the city.
"Shortly after the start of the operation, the vessel was boarded and the assailant was killed," Mr Mutlu said.
"It was clear that the assailant was a terror group member."
Mr Mutlu said the man was between 28 and 30-years-old and was carrying a device with a button and cables which bomb disposal experts were analysing.
However, the governor of Kocaeli province, from where the Kartepe ferry had set sail with six crew and 18 passengers, later told journalists it was a fake bomb.
"There were no bombs on the terrorist. He was wearing bottles and cables that looked like a bomb mechanism," Governor Ercan Topaca said.
None of the passengers were hurt, but some were taken to a hospital for checks after their ordeal.
There was no official word on how the commandos stormed the ferry, but news channels spoke with hostages as they left a police station in the town of Silivri where they had given their accounts of the hijacking.
"The terrorist had told the crew to gather us upstairs, we never saw him. He sent us tea and biscuits," Kadir Altunoglu, a man in his thirties, told Samanyolu news channel
"We heard five or six gunshots before dawn. We had opened the rear exit door of the ferry to let the commandos in."
Another passenger, Ceyhun Tezer (28) told the NTV channel: "It lasted no more than 10 minutes after we saw them (the commandos). We heard six gunshots, they told us three in the head and another three in the chest, there were no more gunshots."
He said passengers were alarmed the ferry was taking too long for the short run between the towns of Izmit and Karamursel and was off course, but only realised it had been hijacked when they saw news reports on the television in the passenger lounge.
NTV also aired security camera footage of a dark-haired man, said to be the hijacker, carrying a sports backpack, walking to the ferry.
Since Friday evening, coastguard vessels with commandos aboard had tracked the "sea bus" in the Sea of Marmara before it ran low on fuel and dropped anchor.
Shortly before 3am Irish time a flurry of activity was evident on the ferry's main deck. Hazy television pictures showed figures moving in the aisle between rows of empty seats. A few people were apparently wearing life jackets.
Transport Minister Binali Yildirim had told reporters in the capital Ankara the hijacker had not made any concrete demands and had only sought fuel, food and drink.
Earlier reports said up to five suspected Kurdish militants armed with explosives carried out the hijacking on the high-speed ferry.
At that stage, Yildirim had said there was evidence the hijackers belonged to a "a wing of the terror organisation", a reference to the militant Kurdistan Workers Party (PKK) which is fighting for Kurdish autonomy in the southeast of the country.
There was no immediate comment from the PKK, which is listed as a terrorist organisation by Turkey, the United States and the European Union.