An emergency official says an explosion inside the Thai prime minister's besieged office compound has wounded 33 people.

A spokesman from the Narentorn Medical Center said early Sunday morning that five had been hospitalized.

Police have not yet responded to the compound that protesters have held since August.

An Associated Press photographer says the device was hurled from outside the compound. It was not clear what was thrown.

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Protesters have also seized Bangkok's two airports — stranding about 100,000 travelers — in their campaign to topple the government.