They said the two men, caught in the act by security cameras, were trying to cause trouble.
The protesters under the PDRC had converged on and surrounded the police station about 8.30am after representatives of political parties filed complaints with the police that they could not enter the Thai-Japanese sports stadium to register their candidacy for the general election called for Feb 2, 2014.
Shortly before noon, as the protesters relaxed outside the station, the sound of firecrackers exploding was heard. This angered the protesters, who complained.
Police asked one of the PDRC’s leaders, Phutthipong Punnakan, to join them in checking footage from CCTV security cameras installed in the parking lot of a hotel next door to the station.
The cameras captured images of two men throwing firecrackers at the station.
The protesters urged the police to arrest the men, saying they were trying to create problems.
According to TV reports, the station was still surrounded early this afternon, with people inside - both police and visitors - unable to leave.
Electricity and the water supply had also been cut off, according to the reports. Police had to negotiate with protesters in order to allow food to be deliver to the station.
The protesters later announced they would allow female Election Commission staff to leave the police station. The rest would be able to leave after 4.30pm.
Chumpol Julsai, another PDRC leader, said the protesters wanted to view the police record, to see if it reported they had obstructed the election or not. The protesters had insisted that they would not obstruct candidacy registration. He said he would safely escort representatives of political parties into Thai-Japanese sports stadium to register.
Registration of party-list candidates for the general election opened at the stadium on Monday, with nine parties registering and 25 others complaining to police they had not been able to enter the venue, where protesters began gathering on Sunday night.