SANAA, Yemen (AP) — A Yemeni security official says gunmen stormed a passenger plane after it landed in the country's south, grabbed an opposition leader from his seat and spirited him away to an unknown destination.

The official says Wednesday's kidnapping took place at the international airport in the port city of Aden. Masked gunmen burst into the airport building first, meeting no resistance from airport security. They then ran onto the runway and boarded the plane.

The official says the motives for the abduction of retired Maj. Gen. Ahmed Abdullah al-Hassani, a former Yemeni navy commander, was unclear.

Al-Hassani was a staunch opponent of former president Ali Abdullah Saleh. After retiring, he became a prominent campaigner for the south's secession.

The security official spoke on condition of anonymity in line with regulations.