Anti-government protesters calling for Thai Prime Minister Yingluck Shinawatra to step down launched a rally in Bangkok on Saturday, Nov 24, that authorities feared would grow into the biggest demonstration the country has seen since she took office last year, The Associated Press reported.

The rally, which was expected to draw tens of thousands of protesters, was mostly peaceful in its early stages. Police, however, fired tear gas to disperse between 50 to 100 people who tried to break through a line of concrete barricades erected on a street near the protest site.

Earlier in the week, Yingluck ordered nearly 17,000 police to deploy and invoked a special security law, citing concerns that the rally could turn violent. She also accused demonstrators of seeking to overthrow her elected government.

The protest was organized by a royalist group calling itself "Pitak Siam" — or "Protect Thailand." Led by retired army Gen. Boonlert Kaewprasit, the group accuses Yingluck's administration of corruption, ignoring insults to the revered monarchy and being a puppet of Thaksin.