SANAA/ADEN (Reuters) - Tribesmen in Yemen freed six U.N. aid workers on Thursday, two days after they were kidnapped to secure the release of a jailed man from police custody, one of the hostage-takers said.
Valerie Amos, the U.N. emergency relief coordinator, had somewhat different information, saying that seven abducted aid workers had been released unharmed, but giving no details on the kidnappers' demands.
It was not immediately clear whether the seventh aid worker was employed by a non-governmental organization rather than the United Nations in Yemen.
"They are now in Sanaa and are in contact with their families," Amos said in a statement thanking Yemeni authorities and all those who worked to secure their safe release.
"This incident serves to remind us of the dangers faced every day by humanitarian workers helping people in crisis situations around the world," she added.
The Yemeni government had earlier said the aid workers - a German, a Palestinian, an Iraqi, a Colombian and two Yemenis who were seized on Tuesday - had been released. But the tribal source said the kidnappers had made a last-minute demand for a fellow tribesman held by police be handed over to them first.
"We freed the hostages after we received the man held by the authorities," the kidnapper told Reuters by telephone.
Electricity and Energy Minister Saleh Sumai, who led the negotiations with the kidnappers, confirmed the hostages were handed over to him and said they were on their way to the capital, Sanaa.
A U.N. source said six of the aid workers worked at the Office for the Coordination of Humanitarian Affairs (OCHA).
Kidnappings are common in Yemen, where hostages are often used by disgruntled tribesmen to press their demands on authorities, and are usually freed unharmed.
The United States and Saudi Arabia are worried that a prolonged period of political disorder and unrest in Yemen could give the regional wing of al Qaeda an opportunity to gain more control of the impoverished country.
In southern Yemen, five Islamist militants were killed in clashes with government soldiers, a security source said, in escalating violence ahead of a presidential election this month.
Protests have continued even after President Ali Abdullah Saleh transferred his powers and bowed to a year of mass protests demanding the end of his 33-year rule.
Activists demand that Saleh, who is in the United States for medical care, be tried for alleged killings of protesters, and the government be purged of his relatives.
Yemenis are due to go to the polls on February 21 to vote for a new president. Many fear that a wave of violence in Sanaa could escalate to derail the vote.
The defense ministry said on Wednesday a leading member of the security forces escaped an assassination attempt in Sanaa.
(Reporting by Mohammed Ghobari in Sanaa and Mohammed Mukhashaf in Aden, additional reporting by Nour Merza in Dubai and Stephanie Nebehay in Geneva; Writing by Nour Merza and Sami Aboudi; Editing by Mark Heinrich)