The Geneva Accords of 1962 made little difference to the fighting in Laos and in the spring of 1964 a major offensive by the Pathet Lao and NVA drove Laotian government troops out of the Plain of Jars.  The government situation became critical and US assistance was requested  to halt a complete collapse.  The Royal Lao government under Prime Minister Souvanna Phouma received T-28Ds and allowed US reconnaissance aircraft to provide intelligence on the movement of the communist forces.  In April Detachment 6 of the 1st ACW (code named Water Pump) was established at Udorn RTAB with four T-28Ds to train Laotian and Thai airmen on the type.  Air America pilots were also trained on the T-28 as they flew the aircraft for close air support and helicopter escort.  In addition to training, the aircraft also took part in operations against the Pathet Lao.  Under the code name Yankee Team, the reconnaissance flights over the Plain of Jars were flown by USAF RF-101s from Tan Son Nhut and Navy RF-8s from TF 77 aircraft carriers.  After an aircraft was shot down on 6 June the reconnaissance aircraft were escorted by fighters.  Detachments of F-100s deployed to Takhli and to Da Nang in South Vietnam to provide escorts for the reconnaissance missions.   On 9 June, following the loss of the second Crusader in Laos, President Johnson authorised the first US retaliatory strike by F-100s against AAA sites in Laos.  Thus started US offensive operations in the northern provinces of Laos in support of government forces that would develop into the Barrel Roll campaign.  Later, in April 1965, US forces started flying missions (under the code name Steel Tiger) in the southern panhandle of Laos specifically against the movement of North Vietnamese traffic along the series of roads and tracks known as the Ho Chi Minh Trail towards South Vietnam.  There were, in effect, two separate wars fought in Laos although both campaigns often used the same resources based in Thailand and at sea.