SANAA - Yemeni forces on Wednesday killed three members of a militant cell who authorities believe attacked a German diplomat late last month and carried out assassinations in the capital Sanaa, a Yemeni official and a security source said. The security source said a counter-terrorism unit raided a house in the Shmailah district in south Sanaa and killed three al-Qaida militants. 'They were behind the attempted killing of the German diplomat,' the security source said.