Thailand's prime minister said his critics planted four small bombs in a southern province in an effort to discredit his administration ahead of a parliamentary no-confidence debate that begins Thursday. The opposition is seeking to censure Prime Minister Abhisit Vejjajiva and five Cabinet ministers, accusing them of mismanaging the country. Abhisit took office in December following months of instability and protests by opponents of former Prime Minister Thaksin Shinawatra, whose loyalists dominate the opposition. Thaksin was ousted in a 2006 military coup; he fled into exile last year and was later convicted in absentia of violating a conflict of interest law. Police Col. Pornsak Nuannoo said officers defused four small explosive devices in Surat Thani province, a stronghold of Abhisit's Democrat Party. One was planted behind a Democrat Party billboard near its provincial office.