The Australian government knew of US intelligence warnings that Bali could be targeted by terrorists, Prime Minister John Howard admitted yesterday in a dramatic reversal of previous claims that no such information had been given. The revelation could lead to a damaging inquiry into what is being branded Australia's darkest day since World War II. Of the 41 people confirmed killed by the bombings, 11 were Australian, with the rest coming from 10 other nations. More than 140 others are missing, feared dead. Over 300 survivors were injured. Mr Howard's about-face came as police announced four Indonesians being questioned will be formally arrested as suspects in the Bali bombings. They denied media reports that another man - a former Indonesian air force member - had confessed to involvement in the blasts. But he was being questioned, had the expertise to make a bomb and was living in Bali, they said. Malaysia said it detained five suspected militants, including one linked to al-Qaeda. Mr Howard told parliament that although the information had been received from Washington two weeks before Saturday's blasts, it was decided not to update travel advice to tourists. The comments follow a report in the Washington Post on Tuesday, which said the CIA specifically cited Bali as an example of a tourist destination in Indonesia that should be avoided. The New York Times reported that Washington warned Indonesia repeatedly that al-Qaeda was planning an attack, with US Ambassador Ralph Boyce delivering the latest warning to President Megawati Sukarnoputri a day before the Bali blast. Mr Boyce called the reports 'imprecise'. Mr Howard said on Tuesday no intelligence mentioning Bali specifically had been passed on to him or to Australian intelligence officials. 'We had no warning of the specific attack that occurred,' he said. Yesterday, however, he said that Bali had been included in recent US intelligence reports as a target of 'possible terrorist activity against United States tourists', along with other tourist and cultural attractions across Indonesia. 'This intelligence was assessed by agencies and the view formed by them [was] that no alteration in the threat assessment level, then at a high applying to Indonesia, was warranted,' Mr Howard said. The US Embassy in Jakarta apparently acted on the CIA report and issued two travel notices, on September 26 and October 10, warning Americans to 'avoid large gatherings and locations known to cater primarily to a Western clientele, such as certain bars, restaurants and tourist areas'. In contrast, the Australian Department of Foreign Affairs' most recent travel advice before the bomb attack, released on September 20, said that while Australians should be aware of the risk of bombings in Indonesia, tourist services in Bali were operating as normal. Mr Howard launched a review yesterday of all intelligence material received by Australian spy agencies, and announced a reward of A$2 million (HK$8.5 million) for information leading to the arrest and prosecution of whoever was responsible for the bombings. But Bob Brown, a senator with the Australian Greens party, called for a parliamentary inquiry to find out whether there had been an intelligence blunder. 'There are serious concerns about the intelligence warnings or failure to warn. It is easy to be wise in hindsight but it's part of our role as parliamentarians to make sure that we do review the warnings, or the failure of warnings, before the Bali bomb blasts,' he said.