By Evelyn Leopold UNITED NATIONS, June 11 (Reuters) - U.N. Secretary-General Ban Ki-moon wants the world body to play a larger role in Iraq but has had to withdraw personnel from the south and proposed a new U.N. building in the international "Green Zone" to protect staff in Baghdad, according to a report circulated on Monday. Ban, in his report to the 15-nation U.N. Security Council, said that "circumstances permitting, I would consider an expanded role and presence in Iraq where possible." U.S. Ambassador Zalmay Khalilzad, in an interview with Reuters last month, said the United Nations should be more involved in internal reconciliation efforts and drawing in Iraq's neighbors to help stabilize the country. But both Khalilzad and Ban were vague on exactly what was entailed in addition to current legal, political and electoral activities. Ban last month also launched the International Compact for Iraq in Sharm el-Sheikh, Egypt, to raise money for Baghdad from regional countries and beyond. Security, however, has prompted the United Nations to withdraw staff from the oil port city of Basra, in Iran's south, as British forces prepare to pull out of the nearby Basra Palace base to the airport on the outskirts of town. But Ban said he was exploring the possibility of a new U.N. location in Basra in the future and of expanding U.N. personnel in Irbil in the north. At the same time Ban said protection of U.N. staff living in Baghdad's Green Zone was precarious due to insufficient "overhead protection" that could withstand rocket attacks. Consequently, "the only long-term solution to this dilemma is the expeditious construction of a hardened integrated compound, with the necessary structural integrity to withstand impacts from high-calibre ordnance." A new building, Ban, said would "make the difference between the U.N. mission being able to operate effectively in the future or having to wind down operations due to the unacceptable security risks currently faced by the mission." He said he would make arrangements for the construction expeditiously, despite anticipated high costs because "there is no realistic alternative if the mission is to continue operations." The sprawling Green Zone is the most heavily protected area in the capital, but it has come under increasing mortar and rocket attack. The attacks have also become more accurate and deadlier in recent months, some from nearby Shiite neighborhoods. On Aug. 19, 2003, U.N. headquarters in Baghdad was bombed, killing 22 staff and visitors, including the head of mission, Brazilian Sergio Vieira de Mello.