"I affirm that this group is behind the Marriott bombing, based on intelligence reports following the arrest (last month) of nine suspects who are also JI members," Antara quoted Jalil as saying overnight at Makassar in South Sulawesi province.

Police in July arrested nine suspected JI members near Jakarta and at Semarang in Central Java. One of them allegedly killed himself in police detention.

Officers said they seized JI documents, TNT, rifles, potassium chlorate and shoulder-launched rockets in the raids.

Police later said that "about five" political leaders and high-profile individuals were named in the seized documents, which also named several shopping centres as targets.

Jalil said intelligence documents indicated that JI was behind a series terror attacks in the country in recent years.

Police said Friday a severed head found at the scene of Tuesday's hotel bombing belonged to a JI member identified as Asmar Latinsani, 28, a native of West Sumatra.

Police had sketched a reconstruction of the head, which was found on the fifth floor of the hotel. Ten people died and 146 were injured in the car bombing.

JI, which is thought to be linked with al-Qaeda, is also blamed for the Bali bombings last October, which killed 202 people, and a string of other bloody attacks in the region. It seeks to establish a pan-Islamic state in much of Southeast Asia.

Indonesia's top detective Erwin Mappaseng said Latinsani had been recruited by two JI members, who were arrested between the Sumatran cities of Medan and Pekanbaru before the Marriott blast.

Mappaseng did not say if Latinsani was believed to be the driver of the locally-made Toyota Kijang van.

National police chief Da'i Bachtiar said detectives already have names and pictures of people who were wanted before the Marriott blast. Police now wish to question them about the attack.

Meanwhile, the United States warned Friday that extremists could be plotting more attacks against Americans or US interests in Indonesia.

"The US government believes extremist elements may be planning additional attacks targeting US interests in Indonesia, particularly US government officials and facilities," the State Department said in a travel warning.

The warning said that as security was increased at high-risk installations, extremist groups could chose to go after so-called "softer" targets like places where Americans or Westerners live.

Also cited as high-risk spots were hotels, restaurants, nightclubs, schools and places of worship.

On Thursday, Indonesian Islamic militant Amrozi was sentenced to death for the Bali bombings. He was accused of buying the chemicals used in the blasts and the van and transporting them to the holiday resort.

The State Department warning reiterated previous warnings for Americans to defer all nonessential travel to Indonesia.

WAR.WIRE