BANGKOK , Thailand ( CNN ) -- Flights into Thailand have been thrown into chaos Wednesday after explosions at two Bangkok airports wounded four people and triggered the closure of its main international gateway -- a major hub in the region for travelers , authorities said . Passengers face a long wait inside Suvarnabhumi airport with most flights canceled . The blasts come a day after thousands of anti-government protesters stormed the airports to protest the return of Thai Prime Minister Somchai Wongsawat from the APEC summit in Peru . One blast occurred at Suvarnabhumi Airport at 5 a.m. ( 2200 Tuesday GMT ) , an airport official said . One person was wounded in that attack . Continued protests caused authorities to cancel all incoming and outgoing flights there , an assistant to airport director Serirat Prasutanond told CNN . Three protesters also entered the airport 's control tower , demanding the prime minister 's flight schedule , The Associated Press quoted Group Capt . Chokchai Saranon , a control tower official , as saying . As the airport had been shut down , there were no controllers in the tower , AP reported . Watch what 's behind protesters ' demands » . The other blast occurred at 6:40 a.m. Wednesday ( 2340 Tuesday GMT ) at the Don Muang International Airport , wounding three people , police said . Suvarnabhumi Airport later canceled all flights , AP reported . On Tuesday thousands of anti-government protesters partially shut down Suvarnabhumi Airport , the country 's main airport , an airport spokesman said . Watch fists fly in the terminal » . Pro- and anti-government protesters also exchanged gunfire , a Thai police official said . Protesters with golf clubs and long wooden sticks also clashed with airport taxi drivers , with each side throwing things at the other . The clash started when the anti-government group People 's Alliance for Democracy ( PAD ) was mobilizing supporters near the Don Muang airport , which the government is using as its temporary office . iReport.com : Are you there ? Send pics , video . The PAD ran into a pro-government group , resulting in an exchange of abusive words , and the pro-government group threw rocks into the PAD crowd prompting an exchange of gunfire , the police official said . The PAD has been leading protests against the government since May , accusing the government of being a front for ousted former Prime Minister Thaksin Shinawatra . Protesters surrounded the parliament building on Monday , forcing lawmakers to postpone their session . Thaksin was ousted in a bloodless coup in 2006 , only to return after the People Power Party won elections in December 2007 . He left again in August of this year , shortly before he was to face trial on corruption charges . In October Thailand 's Supreme Court ruled that Thaksin had abused his powers while in office and sentenced the absent former leader to two years in prison . The case was one of several lodged against Thaksin , who protesters want to return to Thailand to face trial . Thaksin stayed in the United Kingdom for much of this year before British authorities revoked his visa . CNN 's Kocha Olarn contributed to this report . Copyright 2008 CNN . All rights reserved.This material may not be published , broadcast , rewritten , or redistributed . Associated Press contributed to this report .
NEW : Authorities cancel all flights at Don Muang International Airport after blast ; Three wounded . Three people wounded at blast at Suvarnabhumi Airport . Pro- and anti-government protesters exchange gunfire . the People Power Party has been leading protests since October Thailand 's .