Yemeni officials say pro-government forces in the southern port city of Aden are detaining and evicting to the north hundreds of civilians.

They say armed groups have been raiding shops, restaurants and homes, arresting more than 2,000 northerners they say pose a threat to "security."

The officials say they suspect the evictions are the work of secessionists who want southern Yemen to break away from the north, with which it was united in 1990.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

Aden was among the first cities where forces of the internationally recognized government drove out Shiite rebels as part of Yemen's war pitting government forces, backed by a Saudi-led coalition, against Shiite rebels known as Houthis and their allies.