Around 400 people have been killed -- the majority Rohingya Muslims -- in communal violence in Myanmars Rakhine State, the office of Commander-in-Chief Min Aung Hlaing said Friday. "Until August 30, a large number of terrorists carried out 52 waves of attacks on security forces.... in those attacks, 370 bodies of terrorists were found and nine others captured alive," a statement posted on Facebook said, alluding to Rohingya fighters. Fifteen security forces and 14 civilians have also died in eight days of fighting, it added. The UN says 38,000 have sought refuge across the border in Bangladesh.  According to Agence France Presse, 20,000 Rohingya have massed along the Bangladeshi frontier, barred from entering the South Asian country, while scores of desperate people have drowned attempting to cross the Naf, a border river, in makeshift boats. UN chief Antonio Guterres warned Friday of a looming humanitarian catastrophe in western Myanmar. "The secretary-general is deeply concerned by the reports of excesses during the security operations conducted by Myanmars security forces in Rakhine State and urges restraint and calm to avoid a humanitarian catastrophe," said a UN spokesman. The latest round of violence erupted last Friday when Rohingya militants swarmed remote police posts, killing 15 officials and burning villages.