An Internet blog purportedly speaking on behalf of a group calling itself "Al-Qaeda Organisation Indonesia" has claimed responsibility for the July 17 Jakarta hotel bombings.
The entry was posted on the Google site blogspot.com on Sunday but was only discovered on Wednesday and reported in the Indonesian media.
The message in Indonesian and Arabic was signed by "Abu Muawwidz Nur Din bin Muhammad Top" and praises two "holy warrior brothers" who blew themselves up at the JW Marriott and Ritz-Carlton hotels in central Jakarta.
Two suicide bombers killed seven people including six foreigners in the coordinated blasts at the adjacent luxury hotels.
Police have said the attacks bear the hallmarks of Malaysian Islamist Noordin Mohammed Top.
Noordin is suspected of masterminding suicide bombings in Indonesia in 2003, 2004 and 2005 which killed a total of 42 people and injured scores more.
Police were not available to comment on the claim, which could not be independently confirmed.
Terrorism analyst Sidney Jones, of the International Crisis Group, said she could not say whether the claim was authentic but noted that blogs were "often used by some of the jihadi groups".