Shots fired by unknown gunmen have today rattled parts of Bangkok where anti-government protesters have set up camp.
National security chief Paradorn Pattanathabutr said there had been no reported deaths or injuries in the incidents in the Thai capital in the early hours of today.
''As for the perpetrators, we still don't know who they are,'' he said.
''Recently we have been seeing more incidents like this happening more frequently... it is noticeable that there are incidents like this every day.''
At the weekend five people were killed in violence in the city and the eastern province of Trat - four of them young children.
The protesters, whose disruption of a general election this month left polarised Thailand in political paralysis, aimed to topple Prime Minister Yingluck Shinawatra and erase the influence of her brother, ousted premier Thaksin Shinawatra, seen by many as the real power in the country.
The protesters wanted to set up an unelected ''people's council'' of the good and worthy to oversee vaguely defined political reforms, including a restructuring of the police force, before new elections were held.
Occasional contact between the two sides, amid calls for putting an end to the violence, has so far led to nothing.
Bluesky TV, the protesters' TV station, showed demonstrators pushing against the wrought iron gates of the national police headquarters in Bangkok, demanding the proper investigation of more than 20 deaths since the beginning of the protests.
Protesters have vilified the police as lackeys of Thaksin, himself a former police officer.
''We want the police to do their job honestly and straightforwardly,'' said Anchalee Paireerak, a protest leader and former television news anchor.
''We urge them to stop serving the Thaksin regime and join our movement.''