 Additional battalions were later identified as coming from the 29th Regiment of the 325C Division, the 90th and 803rd Regiments of the 324B Division and the 24th Regiment of the 304th Division, three of these Regiments were believed to be involved in the siege of Khe Sanh.Allied intelligence estimated that 16–18 PAVN Battalions totaling 8–11,000 soldiers were engaged in the battle.Allied air and artillery support was restricted by the poor weather, supply difficulties and, initially, by restrictions intended to limit damage to Huế's historic structures.