Yemeni security forces were on Saturday hunting for suspected Al-Qaeda gunmen who abducted a Swiss woman this week with no immediate leads in sight, a security official said.
"We are pursuing our search but so far we have not been able to locate where the Swiss woman is being held or know anything about her fate," a security official in southern Shabwa province told AFP.
He said that three suspects were detained overnight as part of the investigation.
On Friday a local official said suspected Al-Qaeda gunmen seized the woman in the Red Sea port of Hodeida and then moved her to restive Shabwa province further to the east.
The Swiss foreign ministry confirmed the abduction and said it had been informed the woman had been kidnapped late Wednesday and were trying to seek her release.
The Yemeni interior ministry, quoting a Swiss colleague of the woman, said she had been teaching at a foreign language institute in Hodeida and was seized at home by "men in military uniform" who moved her to Shabwa.
The colleague identified her as 34-year-old Sylvia Abrahat, according to the transliteration from Arabic of a name posted by the ministry on its website.
According to the report, the kidnapped woman telephoned her colleague to say her abductors are demanding "the release of prisoners held in Hodeida" in return for her freedom.
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The local official who announced the abduction on Friday said at the time that the kidnappers were "demanding the release of two Al-Qaeda militants detained in Hodeida."
Later a security official said "the kidnapping bears the hallmark of Al-Qaeda".
According to him, only a well-organised group such as Al-Qaeda could have undertaken such an operation, which involved moving the Swiss woman across three provinces.
Shabwa is a stronghold of loyalists of the jihadists' local affiliate Al-Qaeda in the Arabian Peninsula, or AQAP, whose militants fight under the banner of Partisans of Sharia (Islamic law).
A tribal source said the woman was being held in a mountainous area of Shabwa adjoining Bayda province.
"Contacts are under way in an attempt to secure the woman's release," he told AFP, without detailing the nature of the contacts.
The source named the men whose release is wanted by the kidnappers as Ahmed Mohammed Morjan and Faez Mohammed Aliwa -- both said to be detained from criminal issues.
Overnight Friday authorities arrested Morjan's father, a brother and a cousin to quiz them on any involvement in the abduction, the security official said.
More than 200 people have been abducted in Yemen during the past 15 years, many of them by members of the country's powerful tribes who use them as bargaining chips with the authorities.
Almost all of those kidnapped were later freed unharmed.