While Sihanouk was out of the country on a trip to France, anti-Vietnamese rioting took place in Phnom Penh, during which the North Vietnamese and NLF embassies were sacked. It seems likely that this rioting was at least tolerated, and possibly actively organised, by Lon Nol, the Prime Minister, and his deputy Prince Sirik Matak. On 12 March, the prime minister closed the port of Sihanoukville – through which weapons were being smuggled to the NLF – to the North Vietnamese and issued an impossible ultimatum to them. All PAVN/NLF forces were to withdraw from Cambodian soil within 72 hours (on 15 March) or face military action.