BANGKOK — As protests demanding elections grew in Bangkok, Thailand’s military junta on Sunday warned Thais against opposing military rule, saying “the process of democratization cannot be carried out right now.”

A statement by the coup leader, Gen. Prayuth Chan-ocha, which was read out by a subordinate on television Sunday, said the military sought to “bring back happiness to all Thai people.”

“We would like to urge cooperation from all civil servants and police to be patient, sacrifice and accept the principle of ridding the country from conflict,” the statement said. “Otherwise, we will become a failed state and no one will be happy.”

The military over the weekend ordered two dozen professors and writers to turn themselves over to the military authorities, broadening a sweep in which nearly 200 political officials have already been summoned and detained.