If this were the case, Helble concluded that the United States should tell Diệm that his regime must condemn the actions of the troops and punish the culprits. If Diệm refused, the United States should threaten to publicly condemn and distance itself from Saigon. With the US also decrying the use of troops against civilian protests, the South Vietnamese government complained that unlike their Saigon counterparts, the Huế police were not trained in riot control. Diệm's authorities requested that the Americans airlift 350 military personnel from Vũng Tàu in the far south to quell the protests in Huế, but the Americans refused. William Trueheart, who was in charge of the US Embassy, Saigon while Ambassador Frederick Nolting was on holiday, confronted Secretary of State Nguyễn Đình Thuận about the allegations of blister gas usage the next day. Thuận appeared to be astounded and asked Trueheart what blister gas was. Trueheart explained that the symptoms of the victims were consistent with those of mustard gas and passed on the US threat to denounce the regime for the chemical attacks. The day after the attacks, there had been press reports that the US Air Force had been used to transport troops of the Airborne Division to Huế, but this was denied two days later by a State Department spokesperson who said that no US aircraft or personnel had been involved in the transport of any Vietnamese servicemen or policemen.