Tear gas has been used at Chamaimaruchet Bridge near Government House and at an intersection near Metropolitan Police Headquarters.
The Centre for Administration of Peace and Order (CAPO) said the tear gas was necessary to handle protesters in accord with international standards, as protesters tried to enter the restricted areas.
Anti-government protest leader Suthep Thaugsuban later on Sunday evening blamed police on deaths and injuries of Ramkhamhaeng University students. He also called for work stoppages by civil servants tomorrow and urged free TV stations to stop airing government announcements.
Meanwhile, Thai Prime Minister Yingluck Shinawatra is still in the country and has not departed for South Africa, as rumours swirled, a senior Thai government official said today.
Wim Rungwattanachinda, secretary to the Minister of Prime Minister's Office, announced as news spread among social media that the Thai premier is preparing to board a plane to the African country amid political chaos in the country.
Mr Wim said the prime minister attended a security meeting at the headquarters of the Drug Suppression Police Division this morning.
He said the premier is still in Thailand but her location cannot be revealed for her safety. She has been monitoring the situation closely and has instructed police to avoid using violence against the protesters, adding any action taken to disperse the crowd must be comply with international standard practices.
Thai Airways International today issued a statement following the leakage of the premier's flight details for South Africa, saying that the booking for Ms Yingluck and her entourage is scheduled to visit the African nation December 1.
The statement explained, however, that the flight was cancelled a month ago as the South African government asked that the the trip be postponed as it must prepare for a general election there.
On an economy-related matter, Thailand's central bank asserted that money was sufficient for withdrawal at ATM machines after the electricity of two of Thailand's major telecommunications companies -- CAT Telecom and TOT -- were cut.