Rally leaders on Bangkok's Ratchadamoen Avenue on Thursday demanded the revocation of Section 112 of the Criminal Code, the lese majeste law, and an end to its use against protesters, who were demonstrating legally.
At a rally at the October 14 Memorial on Constitution Day, protest leader Parit "Penguin" Chiwarak said 25 people were being prosecuted under Section 112, even though authorities had earlier promised not to use it.
The use of Section 112 would result in endless political conflict, and demonstrators would gather wherever lese majeste charges were laid, he said.
Mr Parit said his group would do whatever it could to bring an end to Section 112. He was not afraid of the law.
They would soon open a new website, Nø112, to compile and present information about people prosecuted under Section 112.
Another group demonstrated in front of the United Nations Conference Centre and asked the UN and the international community to pressure the Thai government to repeal Section 112 and to stop using it against rally leaders.
Pol Maj Gen Piya Tawichai, Bangkok deputy police chief, said police from Chana Songkhram and a bomb squad had been sent to the October 14 Memorial after receiving a complaint that a pipe bomb was thrown there in the early morning.
Pol Lt Col Pitiphan Kridakorn na Ayutthaya, deputy chief of Chana Songkhram station, said demonstrators reported that a suspicious object was hurled into the area about 3am.
Police found plastic pipe scraps and nails, but had yet to determine what the object was, he said.