Hundreds of riot police and thousands of anti-government red shirted protesters faced off Friday morning at a key intersection in Bangkok's business district after Thursday night's blasts in the area where three people were killed and 75 injured.

Police armed with batons and riot shields asked red shirts to clear the barricade which is made up largely of tyres.

Deputy Prime Minister Suthep Thaugsuban said that three people were killed and 75 other people were wounded when attackers shot five M-79 grenades last night.

A series of bomb blasts rocked Bangkok's main financial district of Silom on Thursday night as the red-shirted anti-government protesters were confronting with pro-government groups.

TPBS TV said earlier that a woman died after she was rushed to the Chulalongkorn Hospital in Bangkok.

Among the targets of the series of blasts, the Headquarters of Bangkok Bank, Thailand's largest commercial bank, was hit by a bomb, leaving more than 20 injured, local media reported.

The blast occurred around 09:00 p.m., following three explosions that hit the third floor of Sala Daeng skytrain station, the sky walk and Dusit Thani hotel.

Sansern Kaewkamnerd, spokesman for the Center for the Resolutions of Emergency Situations or CRES confirmed that the explosions were caused by M-79 grenades.

Bangkok Skytrain authority has suspended services of four stations and the Subway authority has suspended services of five stations after the bomb blasts.

Meanwhile, the red-shirted protesters who camped nearby lit at least 10 fireworks to prevent army helicopters from entering the area.

Police have captured six suspects in Silom area and investigation is under way, Nation TV said late Thursday night, hours after the blasts.

However, the red-shirts leaders earlier denied that they have any connection with the blasts.

The anti-government red-shirts started their protest rally in the capital a month ago, demanding Prime Minister Abhisit's resignation and dissolving the lower House of the parliament for new elections.