Protests mainly prompted by social media are occurring in Thailand's capital Bangkok despite warnings by the country's new military rulers.

The generals overthrew the government on Thursday after months of confrontation between the government of Prime Minister Yingluck Shinawatra and the royalist establishment.

Al Jazeera's Robert Kennedy, reporting from Bangkok, said several hundred protesters gathered in front of a McDonald's fast-food restaurant in the city's central business district, where soldiers with riot shields met them.

Chants of "Aok bai!" (Go away) rang out loudly through the cheering and jeering crowd, as soldiers sternly looked on.

Pushing and shoving broke out but there was no serious violence, Kennedy said.

"I think this coup is so bad," said a woman who asked to be identified only as Urai to protect herself. "The government was good and Red Shirts are good. These soldiers are bad."

At the same time on Sunday, the military began meetings with the leaders of state and private commercial organisations, senior officials of the commerce, finance ministries and business leaders.

Officials from the Energy Ministry, oil trade and transport companies were due to meet military officers later in the day.

The army has also asked 18 newspaper bosses to a meeting on Sunday, presumably to receive directions on supportive coverage.

"From now on, the army will focus on solving the country's problems," a senior military official said on Saturday.

"The army would like to be in power for the shortest period they can. They want to make sure the country is really getting back to normal without any resistance."

Army's warning

Power now lies squarely in the hands of army chief General Prayuth Chan-ocha and his military government known as the National Council for Peace and Order, and their priorities appeared to be stamping out dissent and tending to the economy.

"We would like to ask all people to avoid gathering to stage protests because it's not a usual situation for the democratic process," Winthai Suvaree, the deputy army spokesman, said in a televised statement.

"For those who use social media to provoke, please stop because it's not good for anyone. For media, they should be careful about speaking, criticising or doing anything that causes damage to any party, especially civilian, police and military officials."

Critics say the coup will not end the conflict between the rival power networks: the Bangkok-based elite dominated by the military, old money families and the bureaucracy, and an upstart clique led by Thaksin Shinawatra, Yingluck's brother and former telecommunications tycoon.

The Shinawatras draw much of their influence from the provinces.

The military has detained leaders of the ousted government including Yingluck and an unknown number of her ministers, party officials, and supporters.

It has thrown out the constitution, censored the media and on Saturday it dismissed the upper house Senate, Thailand's last functioning legislature, in what amounts to a clean sweep of the political landscape.

Politicians detained

Less than 72 hours after the coup, the military has already met political, media, academic and civil service groups.

Many of the politicians have been detained while others such as civil servants have been exhorted to work for the country.

The military, which has launched 19 successful or attempted coups since the end of absolute monarchy in 1932, has banned gatherings of more than five people and imposed a 10pm to 5am curfew.

That has not deterred some critics.

About 200 people marched in Bangkok on Saturday, many with handwritten signs such as "Anti the Coup" and "Get out Dictators".

There was some scuffles with police and several people were detained but no serious violence.

Such small protests appear spontaneous and leaderless but the real danger for the military would be a sustained mass campaign by Thaksin's "red shirt" loyalists.

Protesters said they were organising on social media and were keeping gatherings small in the hope that they would avoid provoking a military response from the army.

Opposition stronghold

About 200 people gathered on Saturday in the northern city of Chiang Mai, Thaksin's hometown, and soldiers detained at least six people, a Reuters reporter said.

At a meeting in Chiang Mai, the army ordered police and officials to squash anti-army dissent or face transfer.

The call reflects the army's unease about control of the north and northeast, hotbeds of support for the Shinawatras.

Six months of anti-government protests that finally led to the coup, the latest outbreak of a nearly decade-long clash between the establishment and Thaksin, have hurt Southeast Asia's second-largest economy.

In the first quarter of the year, the economy shrank 2.1 percent and there is little prospect of improvement.

Thais are not spending, and consumer sentiment fell to a 12-year low in the months before the coup.

Many countries have issued travel warnings for Thailand, which was already expecting the lowest number of foreign visitors in five years in 2014. Tourism accounts for about 10 percent of the economy.