A senior Yemeni intelligence officer investigating the abduction and killing of foreigners has been assassinated in the country's capital, Sanaa.
Yemeni security officials told Associated Press news agency that Colonel Khaled al-Khawlani was killed in a drive-by shooting in front of his house on Wednesday.
Al-Khawlani was investigating a possible link between al-Qaeda-linked groups and the abduction and killing of foreigners in the country.
Yemen has seen dozens of police and military officers assassinated in apparent retaliatory attacks for the government's offensive against al-Qaeda hideouts in the south.
In addition to an an al-Qaeda insurgency, the government is also facing a southern separatist movement and a Shia Houthi rebellion in the north.
Clashes between Shia Houthi rebels and Yemen's military in the northern city of Amran on Tuesday night killed 13 civilians when their homes collapsed.
The fighting erupted when the Houthi fighters attacked government forces near the University of Amran, in the western district of the city, a tribal chief said, adding that "dozens of houses and shops" were destroyed.
A medic from Amran's main hospital said on Wednesday that five children and two women were among the casualties following the "overnight clashes".
Houthi fighters have been battling the central government for years from their heartland in the north, complaining of marginalisation from the capital Sanaa.
Fighting between troops and the Houthis neared Sanaa on Friday, with clashes reaching the town of Bani Matar, only 15km northwest of the capital, tribal and security sources said.
The Houthis have advanced out of their northern mountain strongholds towards Yemen in a suspected attempt to expand their sphere of influence as Yemen is reorganised into six regions in a planned transition to democracy.