Updated

The head of Thailand's military government has warned people against making a political issue after a plaque marking the country's 1932 transition to democracy was ripped and stolen from a public plaza.

Prime Minister Prayuth Chan-ocha said Tuesday that protests over the incident would interfere with what he described as his government's efforts to move the country forward.

Srisuwan Janya, a veteran social activist, was detained by soldiers when he tried to submit a letter to Prayuth asking that the act of vandalism be investigated.

Police have declined to do so, saying there was no one with standing to make a complaint of theft because the plaque had no known owner.

The plaque was replaced by one celebrating the monarchy.