Ouagadougou - One Italian and two Spanish hostages freed by kidnappers linked to al-Qaeda in Mali headed home on Thursday after an accord which mediators said involved a prisoner swap.

The three aid workers, captured in Algeria last October, were flown home to Europe from the Burkina Faso capital Ouagadougou.

The Burkina officer who headed the operation said two Islamists in jail in Mauritania had been released as part of a deal with Mali's MUJWA, the al-Qaeda splinter group which had been holding the hostages.

“I am well, and I hope to continue working in international co-operation,” Italian Rossella Urru said as she was welcomed at Rome airport by elated family members, Prime Minister Mario Monti and Foreign Minister Giulio Terzi.

“This will not stop me.”

Urru said she had been treated well and thanked the Italian government for its efforts to secure her release.

“Welcome back to Italy. Never has a welcome been given with such warmth and joy,” Monti told the former hostage.

Spaniards Enric Gonyalons and Ainhoa Fernandez were flown to Spain on a separate flight.

“It was a release in exchange for a release,” said General Gilbert Diendere, the officer who led the mission, adding that one of two Islamists freed in Mauritania had already been transferred to Mali.

He did not name the Islamists but Mauritanian media and an Islamist prisoner there said on Wednesday that Mamne Ould Oufkir, a suspect in the original kidnapping, had been freed.

The north of Mali is in the hands of local Islamist groups who first fought alongside and then outflanked Tuareg-led separatist rebels who routed government forces there in early April.

Diendere declined to comment on whether a ransom had also been paid to end the aid workers' captivity, one of a spate of hostage dramas in Africa's Sahel region.

Security experts say multi-million-dollar ransom payments are usually made, though never confirmed, by authorities.

There has been no official comment from Madrid or Rome on the circumstances of the release of the aid workers, who were seized in a refugee camp near Tindouf, Algeria.

The trio's departure from the Malian region of Gao, which is in the hands of various Islamist groups linked to al-Qaeda, was delayed on Wednesday by a sandstorm that prevented aircraft sent by Burkina Faso from picking them up.

“It was the most difficult mission,” said Diendere. “The weather was awful and we had to sleep outside in the pouring rain before being able to take off this morning.” - Reuters