The 15 British service members held in Iranian custody for nearly two weeks flew out of Tehran Thursday aboard a British Airways jet bound for London, according to Tehran's Mehrabad Airport flight information.
The plane took off at 8:40 a.m. (5:10 a.m. GMT), according to the airport information.
The British Airways Web site listed the plane as departing at 8:28 a.m. (4:58 a.m. GMT). The plane is scheduled to land in Britain's capital around noon (11:05 a.m. GMT) after a six-hour flight.
Britain's ambassador to Iran and other members of the British embassy saw the personnel off at the airport, Iran's state-run IRIB network reported.
Earlier, the group shook hands and made small talk with Ahmadinejad Wednesday, thanking him shortly after he announced their pardon.
The 14 British men were dressed in suits, the lone woman wore slacks and a kerchief on her head, as they approached the president, who stood next to an interpreter.
Fragments of sentences could be overheard: "Grateful for forgiveness," "Thanks to you and the Iranian people," and "You were kind to us. Thank you very much."
Ahmadinejad joked with one of them, "What kind of compulsory trip were you on?" He then added, "I wish you success."
Ahmadinejad announced the release of the British personnel at the end of a more than hour-long news conference, taking journalists by surprise.
"I declare that the people of Iran and the government of Iran -- in full power given their legal right to place on trial the military people -- to give amnesty and pardon to these 15 people, and I announce their freedom and their return to the people of Britain," Ahmadinejad said.
"I request the government of Mr. Blair not to question these people or to place them on trial for speaking the truth," he added, referring to their video confessions, which Britain has rejected.
The decision to release the hostages would have come from Supreme Leader Ayatollah Ali Khamenei, who has the final say on diplomatic, defense and other key issues, CNN's Christiane Amanpour said.
Ahmadinejad maintained that the detainees had violated Iran's territorial waters, and he said that his government had received a letter from Britain promising not to intrude into Iranian waters.
He also praised the Iranian coast guard members who plucked the Britons from a cargo ship they had boarded to check for smuggled goods on March 23. "I want to thank our border guards who bravely protect our borders and also arrested the violators, and I grant them the bravery medal to their commander," Ahmadinejad said.
The Britons' release, he said, was "a gift to the British people."
Relief and shock
The British personnel's families expressed huge relief.
"Well, we were absolutely, totally shocked," said Alison Carman, mother of Lt. Felix Carman, as she stood beside her husband. "It was just unbelievable. It was a bolt out of the blue. We'd been praying for their release, and when it actually happened, I think I fell to the floor, and Paul burst into tears."
"And we'd like to thank the Iranians for their gift to the British people."
In the town of Hayle, a party was under way at the Cornubia Pub, where one of the detained sailors, Nathan Thomas Summers, worked before joining the Royal Navy.
"We haven't gotten any news yet, but the Ministry of Defense and the Royal Navy have been absolutely fantastic keeping us up to date with every bit of information we've needed," said Summers' mother, Tracey Watkins.
"We really will celebrate once I actually see my son on English soil," she said. "That will be the time. When he's in my arms."
She said she was told that Summers would have to undergo debriefing and a physical exam before seeing his family, but he can call them once he reaches the British Embassy.
"As politics is concerned, I try to keep out of it," Watkins said. "I am just glad I'm getting my son back."
British Prime Minister Tony Blair said the announcement comes "as a profound relief, not just to them but to their families that have endured such distress and anxiety over these past 12 days."
"Throughout, we have taken a measured approach: firm but calm, not negotiating but not confronting either," Blair said in a brief statement to reporters.
"To the Iranian people, I would simply say this: We bear you no ill will. On the contrary, we respect Iran as an ancient civilization, as a nation with a proud and dignified history.
"And the disagreements that we have with your government we hope to resolve peacefully through dialogue. I hope, as I've always hoped, that in the future we are able to do so."
In Washington, White House spokesman Gordon Johndroe said: "President Bush also welcomes the news."
Factors behind release
Syria has been undertaking "quiet diplomacy" between Iran and Britain to "resolve the row over the British sailors," Syrian Foreign Minister Walid al-Moallem told Kuwait's state-run newspaper Al-Anba earlier Wednesday.
Iran's president said the Britons' release was a goodwill gesture in honor of last weekend's observance of the birthday of Mohammed, "the holy prophet of Islam -- the center of all goodness."
Another factor was Sunday's Christian holiday of Easter, Iran's state-run news agency IRNA said.
Ahmadinejad said the Britons' freedom was not related to the status of five detained Iranians captured by U.S. forces during a military raid in northern Iraq in early January."We approached the subject on a humanitarian basis. It was a unilateral decision," he said.
Meanwhile, a U.S. military official said Washington officials were considering a request made by Iran to allow Iranian representatives access to the Iranian group. "The request has been made, but nothing has been approved," the official told CNN on Wednesday.