Coup leader General Prayuth Chan-ocha has said that Thailand's king had formally endorsed his position as head of the military council that will run the country.
He also said in a statement he read on television that he would have no choice but to use force if political protests flared up again. He said he aimed for an election as soon as possible but gave no timeframe for a vote.
The army imposed martial law on May 20 and then seized power on May 22 after nearly seven months of political turmoil.
More top news
The hashtag #RoomForManchester was being widely shared.
Witnesses reported hearing a "huge bang" at the venue during the concert on Monday evening.
ITV News travels to Britain's eastern-most city to gauge how the electorate will be casting its votes.