U.N. Secretary-General Kofi Annan on Thursday appointed a former State Department official to represent the United Nations in Washington in an effort to improve ties, dpa said. William K. Davis will head the U.N. office in Washington, a position that will allow him to lobby U.S. Congress as well as meet government officials on behalf of the U.N. A brief biographical note provided by the U.N. headquarters in New York said Davis is an expert on international economic matters, human rights, assistance and peacekeeping. He served in the U.S. Department of State as a liaison officer with Congress dealing with foreign policy matters, counter-narcotics, human rights and post-conflict reconstruction. Davis also worked for the Organization for Economic Cooperation and Development office in Washington and spent eight years as senior legislative aide at The White House and State Department. The U.S. is the largest financial contributor to U.N. activities. But some Congress members have been critical of the world organization's inefficient programmes, wrongdoings in the oil-for-food scheme in Iraq and sexual misconducts by U.N. peacekeepers.