Airlines were flying dozens of empty planes out of Bangkok's international airport Monday as authorities struggled to clear it of protesters to reopen international links and move 100,000 travelers stranded by the crisis, the airport said.

Some 30 planes had been flown out starting Sunday and an additional 50 were to be moved later Monday, some of them to protest-free airports elsewhere in Thailand so that stranded travelers can fly out of the country, said Sereerat Prasutanont, director of the Airports Authority of Thailand.

Thailand's political crisis escalated Sunday when thousands of pro-government activists converged on Bangkok to counter rival protesters who seized the city's two airports last week and have forced the prime minister to run the country from outside the capital.

Explosions Sunday targeting the anti-government protesters injured at least 51 people, officials said, with blasts hitting the prime minister's compound in Bangkok where the protesters have camped out since August and a road near the occupied domestic airport.

Neither the army nor Thailand's revered king have stepped in to resolve the crisis — or offered the firm backing that Prime Minister Somchai Wongsawat needs to resolve the leadership vacuum.

The problem runs deeper than the airport closures. Political violence has added to the sense of drift bordering on anarchy that pervades the country's administration.

No one claimed responsibility for Sunday's blasts, but Suriyasai Katasila, a spokesman for the anti-government People's Alliance for Democracy, blamed the government.

The alliance says it will not give up until Somchai resigns, accusing him of being a puppet of ousted Prime Minister Thaksin Shinawatra, the alliance's original target. Thaksin, who is Somchai's brother-in-law, was deposed in a 2006 military coup and has fled the country to escape corruption charges.

Alliance protesters swarmed the international Suvarnabumi airport late last Tuesday, shutting down operations and stranding scores of planes. Local newspapers said alliance protesters allowed the airliners to leave the airport starting Sunday, but that the departing planes nevertheless dimmed their lights to avoid being noticed by potentially violent protesters.

Some countries were evacuating their nationals by land. The Australian embassy was helping stranded tourists in Bangkok travel by bus to the southern resort island of Phuket, where air traffic has not been disrupted, for onward travel to Australia.

On Sunday, thousands of government supporters wearing red shirts, headbands and bandanas joined a rally against the protest alliance. Some danced and clapped to music blaring from loudspeakers. They have adopted red to distinguish themselves from their yellow-garbed rivals.

"This is a movement against anarchical force and the people behind it," government spokesman Nattawut Sai-Kua told The Associated Press. "They want anarchy so that the army is forced to intervene and stage a coup."

But the army, which overthrew Thaksin among other previous coups, says it has no plans to oust Somchai. Still, the military has failed to back up Somchai's efforts to restore order.

Also staying out of the crisis has been revered 80-year-old King Bhumibol Adulyadej, who as a constitutional monarch plays no open role in politics but who has healed social fractures in the past.

"No one else can fix this. The country is so divided. The only uniting figure we have is the king. If he tells both sides to step back, they will," said 36-year-old coffee shop owner Natta Siritanond.

Nattawut, the government spokesman, denied rumors that Somchai had left the country, saying he was operating out of the northern city of Chiang Mai and traveling to Nakhon Phanom province, a northeastern province 370 miles from Bangkok.

The Federation of Thai Industries has estimated the airports takeover is costing the country $57 million to $85 million a day. Some of its members have suggested withholding taxes in protest.

Somchai declared a state of emergency, but security forces have so far failed to move on the protesters.

The supporters of the alliance are largely middle-class citizens who say Thailand's electoral system is susceptible to vote-buying and argue that the rural majority — the Thaksin camp's political base — is not sophisticated enough to cast ballots responsibly.

They have proposed discarding the one-man, one-vote system in favor of appointing most legislators, fostering resentment among rural voters.

The divisions have slipped into deadly violence. So far, six people have been killed in bomb attacks, clashes with police and street battles between government opponents and supporters.