MAE SAKOEP, Thailand (AP) — Thai soldiers began sending back some of the thousands of people who have fled a series of airstrikes by the military in neighboring Myanmar. That’s according to people familiar with the matter. The insecurity on the border Monday added a new dimension to an already volatile crisis set off by a coup in Myanmar. The weekend strikes sent ethnic Karen people seeking safety in Thailand. They represented another escalation in the violent crackdown by Myanmar’s junta on protests of its Feb. 1 takeover. On Saturday, more than 100 people were killed in and around demonstrations throughout the country — the bloodiest single day since the takeover.