Their Majesties are expected to arrive at Udon Thani airport in the evening before heading to Nong Bua Lamphu and Udon Thani hospitals.
Thursday’s gun and knife attack by a former policeman began at a nursery in Na Klang district and ended with 38 dead, including 24 children. Ten people were injured in the attack, eight of whom are in critical condition.
The shooter was identified as former police officer Panya Khamrab, who later committed suicide at his house on Thursday after killing his wife, son and two other relatives.
On Thursday evening, Privy Council president and former PM General Surayud Chulanont arrived in Nong Bua Lamphu to visit the injured and oversee operations. He said HM the King will provide support to all victims and their families.
Prime Minister General Prayut Chan-o-cha has ordered government agencies and state enterprises to fly the national flag at half-mast on Friday.
PM Prayut expressed his deep sorrow over the incident and asked Thais to support each other so they could bear the hours of loss and cruelty together, said Prime Minister's Office spokesman Anucha Burapachaisri on Thursday.