Gunmen kidnapped a French female aid worker and two Yemenis who were on a mission to the southern province of Lahij in a Red Cross vehicle on Tuesday, government and security officials said.
The Frenchwoman of Moroccan origin was kidnapped along with two Yemenis, one of them a driver, in the town of Msaimeer, some 70 kilometres (40 miles) from the provincial capital Huta, a government official said.
A source from the Red Cross office in the main southern city of Aden identified her as "a French female aid worker who left today for a mission in Lahij."
The woman and the two Yemenis -- a translator and driver -- were in a Red Cross vehicle when they were seized at around noon and taken to the adjacent village of Bashriya, the official said.
A source close to the kidnappers said the hostages were in "good health" and that they "will not be harmed."
They had been heading towards a camp for internally displaced people who have fled to Lahij from the restive southern province of Abyan, where the army is battling Al-Qaeda-linked militants, a security official said.
The same official earlier identified the hostages as two foreigners and a Yemeni driver.
Speaking from Msaimeer, he described the abductors as "an armed gang wanted by the authorities."
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"The kidnappers want to press for the release one of their men, held by Yemeni authorities on criminal charges," he said.
Yemeni tribes often kidnap foreigners to try to put pressure on the authorities. More than 200 foreigners have been seized during the past 15 years, with most later freed unharmed.
The source close to the kidnappers said they were pressing for the release of activists from the (separatist) Southern Movement, Walid al-Sufi, Tariq Abdo, Fawzi Gazem Yassin Muqbel, who were arrested on Monday in Aden, the south's former capital.
The movement, whose members want either secession or increased autonomy for the formerly independent region, was the main organiser of protests in the south earlier this year and last year.
But separatist demands were put on the back burner after nationwide protests broke out in January demanding the ouster of President Ali Abdullah Saleh, who has been in office since 1978.
Residents of the south complain of discrimination by the Sanaa government in the distribution of resources since union between north and south in 1990.
The south broke away again in 1994, sparking a brief civil war that ended with the region overrun by northern troops.
Both officials said they are in contact with the kidnappers to secure the release of the three hostages, while Msaimeer administrative head Hasan Ali said that "negotiations are under way between the abductors and tribal chiefs."
The French foreign ministry said it was still trying to verify the information and that it was in close contact with the International Committee of the Red Cross.
Earlier this month, three French hostages kidnapped by Al-Qaeda militants in Yemen more than five months ago arrived home after being freed. Tribal sources said a ransom was paid.