Royal Navy Seaman Andrew Henderson is re-united with family members at the Royal marines Barracks in Chivenor, North Devon, Western England, following his release from detention in Iran April 5, 2007. (Xinhua Photo)

The fifteen British sailors detained by Iran for nearly two weeks returned safely back to the UK on Thursday, and reunited with their families.

After arriving at London's Heathrow airport at midday, the personnel, eight from the Royal Navy and seven from the Royal Marines, then flew in two Royal Navy Sea King helicopters to Royal Marine Base Chivenor in Devon, southwest England, where they met their families. And after seeing their families, they will have medicals and undergo a debriefing.

The debrief would last for "hours, not days" depending on "what their needs are," according to a Royal Navy spokesman.

British Prime Minister Tony Blair rejoiced at the crew's return, but saddened by the deaths of 4 British soldiers, who were killed in a roadside bomb blast in southern Iraqi city of Basra on Thursday.

"Just as we rejoice at the return of our 15 service personnel, so today we are also grieving and mourning for the loss of our soldiers in Basra who were killed as a result of a terrorist act," Blair said in a press conference outside Downing Street.

Blair said he was "glad" the sailors returned "safe and unharmed," but insisted that "no deal" had been done with Iran to secure the release.

There were "elements of the Iranian regime" that were "financing, arming and supporting terrorism in Iraq," said Blair.

Iranian President Mahmoud Ahmadinejad announced on Wednesday afternoon that Iran would free the British sailors later that day.

The announcement came moments after the president honored the Iranian coast guards who intercepted the British "trespassers."

On Wednesday, Blair welcomed the release of the 15 British sailors and marines taken captive 13 days ago.

"I would like to thank our allies in Europe, our allies in the United Nations Security Council for their support, and also our friends and allies in the region, who played their part; we are grateful to all of them as we are to the officials in the Foreign Office and the Ministry of Defense and here in Downing Street for the work that they have done," Blair said.

It is not clear what prompted Iran to release the sailors and whether it involved some kind of deal.

According to Sky News reports, the British government had made no deal with Iran to secure the personnel and was in dialogue, not negotiations, with Iranians. And Qatar and Syria had played useful roles in the release of British navy personnel.

On March 23, 15 British naval personnel were seized by Iranian forces when they were patrolling off the Iraqi borders. Iran has insisted that the British boats illegally entered its territorial waters, while Britain said its soldiers were in Iraqi territorial waters.

Editor: Yan