SANAA – Yemen said Tuesday it was offering a reward of $25,000 for information leading to the capture of kidnappers thought to have shot foreign hostages.

Three women from a party of nine kidnapped foreigners were found dead in northern Yemen this week, in a rare killing that comes as separatist and militant tensions intensify in a country whose instability has alarmed Western countries and Saudi Arabia.

The reward of 5 million rials ($24,910) from Hassan al-Manna, governor of Saada province where the nine were seized last week, was announced on state news agency Saba.

It said the authorities were searching for the remaining hostages, but gave no more details.

Saba said Monday the three were part of a group of nine -- seven Germans, a Briton and a Korean -- that included three children and their mother, who were kidnapped last week in the mountainous Saada region bordering Saudi Arabia.

A source told Reuters Sunday that one of the German captives was a doctor at a local hospital which the other Germans were visiting. The Briton is an engineer and the South Korean was working with an aid agency.

Two of the dead women were German nurses and one was a Korean teacher, the Yemeni military said in a statement.

If the killing was carried out by tribal forces, it would mark the first time that women hostages have been victims. Two Belgian women, however, were killed in 2008 by gunmen in an ambush that authorities blamed on al Qaeda.

One analyst said the killings bear the hallmarks of al Qaeda but no claim of reponsibility has been has been made.

Yemen says it arrested last week a man described as al Qaeda's top financer in Yemen and Saudi Arabia.

Yemen, the Arab world's poorest country, is struggling with a revolt in the north, a secessionist movement in the south and growing al Qaeda militancy.

The unrest has raised concerns Yemen could slip into chaos and provide a base of operations for al Qaeda or pirates operating in the Indian ocean.

Yemeni authorities have blamed the Houthi tribal group, who belong to a Shi'ite Muslim sect, for kidnapping the nine foreigners, a charge the Houthis denied.

(Reporting by Mohammed Sudam; Writing by Andrew Hammond; Editing by Samia Nakhoul)