Thailand's army chief has called for rival protest groups to engage in dialogue as martial law was imposed in an effort to restore order after months of political turmoil.

Army chief Prayuth Chan-ocha warned that troops, which took control over security responsibilities across the country on Tuesday, would take action against anyone who used weapons and harmed civilians following longstanding anti-government protests that left 28 people dead and hundreds wounded.

"We ask all sides to come and talk to find a way out for the country," Prayuth told reporters after meeting directors of government agencies and other high-ranking officials.

Both pro- and anti-government protesters are camped out at different places in the capital Bangkok and to prevent clashes, the army warned them against marching.

IN PICTURES: Thailand's political crisis

An announcement on military-run television said that the imposition of martial law was not a coup and affirmed that the caretaker government was still running the country 

"The public do not need to panic but can still live their lives as normal," it added.

Thailand's caretaker prime minister Niwattumrong Boonsongpaisan issued his own plea for harmony in the country, telling reporters the government wanted "peace and order to prevail in the country".

Martial law allows the military to take over power from the police and other state authorities. The army can now search people, homes, vehicles and even open letters and messages.

Media censorship

Troops, some in jeeps mounted with machineguns, stopped some traffic from entering Bangkok after the martial law order. They also took up position at intersections and secured television stations, but life went on as normal in most of the city.

Critics accused the army of media censorship after it ordered 10 satellite TV channels, both pro- and anti-government, to stop broadcasting.

Prayuth said rival protesters could remain at their respective rally sites as long as they remain peaceful and stop marching.

Al Jazeera's Veronica Pedrosa, reporting from Bangkok, said the protest sites had been surrounded by solidiers.

She said leaders of the rival sides had been invited to a meeting scheduled for Wednesday wih the head of the Senate, but it was unclear if the meeting would go ahead.

Thailand has been stuck in political limbo since Prime Minister Yingluck Shinawatra and nine of her ministers were dismissed on May 7 after a court found them guilty of abuse of power.

The military, which put down a protest movement against former Prime Minister Thaksin Shinawatra, Yingluck's brother, in 2010, has staged numerous coups since Thailand became a constitutional monarchy in 1932.

The last one was in 2006 to oust Thaksin, who has lived abroad since 2008 but wields political influence and commands huge support among the poor.

Anti-government protesters want a "neutral" prime minister to oversee electoral reforms aimed at ending Thaksin's influence. They disrupted a February 2 election that Thaksin's loyalists looked set to win. It was later declared void.

Source: Al Jazeera and agencies