(Updates with police confirmation, no casualties, background)

By Telly Nathalia

JAKARTA, Nov 3 (Reuters) - Three small petrol bombs exploded in Indonesia's Moluccas islands early on Monday but there were no casualties, local police said.

The bombs went off in Ternate, in North Maluku, at about 3.30 a.m. local time, damaging the governor's office and house, police said.

"The blasts were molotov bombs, no casualties," said Abdul Mutalib, police office in charge at North Maluku, which is a mainly Muslim part of Indonesia. "Police are investigating to find the perpetrators."

Indonesian authorities have stepped up security in some parts of the country in recent days ahead of the imminent execution of three Muslim militants for their role in the 2002 Bali bomb attacks in which 202 people died.

Major hotels in Jakarta already have fairly tight security, but security has been increased in the resort island of Bali and in parts of the main island of Java, particularly around the prison where the Bali bombers are being held. (Reporting by Telly Nathalia in Jakarta; Writing by Sara Webb; Editing by Matthew Jones)

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