Thailand's army declared martial law early Tuesday "to restore peace and order" after months of antigovernment protests, but stressed that a military coup was not underway.

Soldiers entered several private television stations in Bangkok, the capital, after a predawn statement signed by the army chief, Gen. Prayuth Chan-ocha, which said that ongoing political rallies "could impact the country's security and safety of the lives and properties of the public," the Bangkok Post reported on its website.