The International Red Cross says it has withdrawn its 14 foreign staffers from its office in Aden, Yemen, following an attack by unknown gunmen who held employees at gunpoint and made off with cash, cars and equipment.

The Geneva-based International Committee of the Red Cross said Tuesday the staffers were relocated to another of its sites in Djibouti on the Red Sea following the attack on Monday.

Local leader Samer Jarjouhi said the Red Cross office had faced "at least 10 such incidents recently."

Violence in Yemen escalated in March, pitting Iran-allied Houthi rebels and troops loyal to former President Ali Abdullah Saleh against forces including southern separatists, local and tribal militias, Sunni militants as well as troops loyal to President Abed Rabbo Mansour Hadi.