One group of people is believed to have perpetrated both Friday and Sunday's grenade attacks on anti-government protesters, police said.
The first attack hit as protesters with the People's Democratic Reform Committee (PDRC) leader Suthep Thaugsuban led demonstrators in a march along Banthat Thong Road on Friday. One person was killed and 39 wounded.
The second incident took place on Sunday afternoon at Victory Monument. Two hand grenades were thrown at demonstrators, and shots were fired from a pistol as the suspect responsible for the attack fled the scene. The attack left 28 people wounded, four of them seriously.
Deputy chief of the Metropolitan Police Pol Col Adul Narongsak said on Monday that two safety pins and other fragments recovered by police at Victory Monument indicated that the grenades were high-explosive RGD-5s, made in Russia or China.
The grenade used in the Banthat Thong attack was also an RGD-5, which suggested the two attacks were carried out by the same group of people, he said.
Phayathai police have examined footage from security cameras in the area and questioned five witnesses as part of an official probe into the incident, he said, adding that police are now hunting for the suspects.
The Centre for the Administration of Peace and Order (Capo) has meanwhile released a clear video footage of the man who hurled the two hand grenades at protesters on Sunday.
The 30-second video, from a camera in a shop near the protest, shows a man wearing a white T-shirt, a green jacket and a black cap. He carried a black shoulder bag and threw the RDG-5 grenade at a tent behind the PDRC rally stage in the area.
After throwing the explosive device, the suspect fled into Ratchawithi Soi 14 where he was chased by PDRC security guards and protesters. While fleeing, the man lobbed another grenade and fired shots from a .38 pistol, before hiring a motorcycle taxi driver to take him to Charansanitwong area in Bangkok’s Thon Buri district.
Capo asked members of the public to watch the video and offered a 200,000 baht reward for information leading to the suspect's arrest. Shortly after 5pm, the Facebook page of the spokesman team to the Royal Thai Police posted a message saying Metropolitan Police Bureau (MPB) chief Kamronwit Thoopkrachang had increased the reward for the suspect’s arrest to 500,000 baht.
On Monday, the PDRC led its demonstrators to protest at the Government Lottery Office (GLO) and Government Savings Bank (GSB).
The Network of Students and People for Reform of Thailand (NSPRT) also sent convoys of motorcycles to check various government offices they had earlier laid siege to, including the office of the National Economic and Social Development Board (NESDB), the Office of the Attorney General, the Office of the Council of State, the Export-Import Bank of Thailand (Exim Bank), the Small and Medium Enterprise Development Bank of Thailand (SME Bank) and the Region 4 Revenue Office.
Two gun attacks were reported at PDRC protest venues in Bangkok on Monday morning. There were no reports of any injuries.
A motorcyclist on an inbound lane of Chaeng Wattana Road fired gunshots at guards stationed in front of the Thailand Post building at about 3am Monday. The guards used firecrackers to chase off the attacker, Post Today reported.
Shortly afterward a similar attack occurred on guards stationed at Soi Chaeng Wattana 14.
Meanwhile, the United States government is warning its citizens of the "potential risks of travel to Thailand".
The advisory, posted on the US Department of State website, said the situation in Thailand, particularly Bangkok, is unpredictable and will likely prolong.
"US citizens are advised to avoid all protests, demonstrations, and large gatherings. Some protest sites are located near tourist attractions and popular shopping malls, which at times have closed or shortened hours unexpectedly.
"Protests may occur in other areas with little or no prior notice. You should allow extra time when travelling throughout the city or to/from airports. Consider using public transportation. Although many protest activities have been peaceful, increasingly violent incidents have occurred at or near protest sites," the advisory said.
On Sunday, a group of about 300 Thais gathered outside CNN's bureau in Los Angeles, calling on the news agency to deliver "fair and balanced" coverage of Thailand's political situation.
Nakrob Saeng-urai, a representative of the group, said they gathered because they wanted foreign news agencies not only to present pro-government coverage, but to report on the anti-government protesters' movements as well.
He said many Thai expatriates in LA had taken ballot cards for the Feb 2 election but refused to return them to the Thai embassy in LA.
"If we vote 'No' the government may claim that we still support the election," Mr Nakrob said.
Thai expatriate anti-government protesters gather outside CNN's bureau in Los Angeles on Sunday to demand fair coverage of the ongoing political conflict. (Post Today Photo)