Senior US diplomats are visiting several African countries as part of continuing efforts to urge leaders there to press Libyan leader Muammar Gaddafi to leave power immediately. A number of African countries have been reluctant to call for Gaddafi to step down and have criticized the Nato-led military campaign in Libya. Gene Cretz, the US ambassador who left Libya after Gaddafi launched his bloody crackdown on the opposition in February, and Principal Deputy Assistant Secretary of State Donald Yamamoto arrived on Monday in Addis Ababa, the headquarters of the African Union, US State Department deputy spokesperson Mark Toner said. The diplomats "are in Africa to meet with African Union members to discuss the crisis in Libya and the need for Gaddafi to relinquish power now," he said. Toner said the pair met with Ethiopian Prime Minister Meles Zenawi and would meet with African Union Chairperson Jean Ping before leaving Addis Ababa later. They also met with Mahmud Jibril, leader of Libya''s opposition National Transitional Council who was visiting Ethiopia. "They had a productive meeting on the current situation in Libya and agreed on the importance of maintaining international pressure on Gaddafi," Toner said.