The Citadel came under fire again in the early morning hours of January 31, 1968, as part of the Tet Offensive a Division-sized force of People's Army of Vietnam and Viet Cong soldiers launched a coordinated attack on Huế seizing most of the city. During the initial phases of the Battle of Huế, due to Huế's religious and cultural status, U.S. troops were ordered not to bomb or shell the city, for fear of destroying the historic structures; but as casualties mounted in house-to-house fighting these restrictions were progressively lifted and the fighting caused substantial damage to the Imperial City. Viet Cong troops occupied some portions of the citadel while South Vietnamese troops occupied others; and allied warplanes targeted the anti-aircraft guns the communists has mounted on the citadel's outer towers Out of 160 buildings only 10 major sites remain because of the battle, such as the Thái Hòa and Cần Thanh temples, Thế Miếu, and Hiển Lâm Các. The city was made a UNESCO site in 1993. The buildings that still remain are being restored and preserved. The latest, and so far largest, restoration project is planned to conclude in 2015.