 Complete the following phrase:  By 1977 4 SF Group Airborne had becn raised to strength at Phitsanulok after the Special Battalion was fully absorbed by the RTSF. In the same year 1 Airborne Battalion was taken from the SWC and put under the command of 31st Infantry Regiment, 1st Division Kings Guard. In the late 1970s the RTSF was involved with training local village militia units during the height of the Communist Party of Thailand CPT 