Indonesian police seized a cache of bombs on a bus Friday, days after foreign governments warned that terrorists were preparing to launch fresh attacks in the country, the police chief said.

Police arrested 15 passengers, including the driver of the public bus, which was stopped in the West Javanese town of Bandung. Three of the those detained were being questioned "intensively," said West Java (search) detective chief Col. Ahmad Abdi.

"There were two big bombs and seven small bombs," police chief Gen. Da'i Bachtiar told reporters after a Cabinet meeting. He gave no more details.

Media reports described the bombs as primitive homemade devices. It appeared they were being transported in the bus and were not primed to go off.

Earlier, Abdi said the find consisted of detonators and electrical wires in a box. The seizure, about 75 miles southeast of Jakarta, occurred after an anonymous tip, Abdi said.

Police who are hunting wanted Malaysian militants Azahari bin Husin (search) and Noordin Mohamed Top are concentrating their search in West Java.

On Thursday Indonesian authorities ordered a nationwide security crackdown after at least four foreign governments warned that terrorists were planning attacks during Christmas in Indonesia.

Australia's warning was unusually specific, saying it had "credible information" that terrorists could be targeting the Hilton Hotel chain (search) in the country.

The al-Qaida linked terror group Jemaah Islamiyah has launched a string of terror attacks in Indonesia that left 224 people dead, including the 2002 Bali bombings, last year's attack on the J.W. Marriott hotel and the Sept. 9 Australian Embassy blast.