A Malaysian extremist wanted for a string of terror attacks was named on Saturday as the likely culprit behind suicide bombings at luxury hotels in Indonesia that left eight dead and 55 injured.

Police were studying explosives found in the suspects' "control centre" in room 1808 of the Marriott hotel, which was bombed along with its nearby sister hotel the Ritz-Carlton on Friday during the busy breakfast period.

DNA evidence, including a severed head from the remains of two suicide bombers, was also being examined as security was tightened across Indonesia and the Philippines amid warnings of follow-up attacks.

Five foreigners -- three Australians, a New Zealander and a Singaporean -- were identified among the dead as Foreign Minister Hassan Wirayuda put the total toll at eight, including the bombers.

The health ministry had earlier said nine people died in the bombings.

Of the 55 injured, police said that 18 were foreigners including citizens of Australia, Britain, Canada, China, India, Italy, Norway, South Korea, the Netherlands and the United States.

National police chief General Bambang Hendarso Danuri called on hotels and shopping malls across the vast, mainly Muslim archipelago of 234 million people to raise their security protocols in response to the bombings.

The attacks triggered the cancellation of a planned Manchester United friendly against an Indonesian All-Star team scheduled for Monday, a decision which caused bitter disappointment among football fans here.

On Saturday the glamour side rejected an Indonesian presidential aide's plea to reconsider their decision, saying it had not been made lightly.

"Everyone at the club is disappointed not to be able to play in Indonesia, but it has a responsibility to its players and staff," it said in a statement.

No group has claimed responsibility for the bombings, but the security ministry's anti-terror desk chief, Ansyaad Mbai, told AFP there was evidence pointing to Malaysian-born extremist Noordin Mohammed Top.

"There are strong indications that Noordin Top's group is behind the attacks because the bombs were hand-made and the tactic was suicide bombings," he said.

It is the fourth attack in Indonesia allegedly masterminded by Noordin after bombings at the Jakarta Marriott in 2003, the Australian embassy in 2004 and Bali restaurants in 2005 which have killed more than 40 people.

He is a violent jihadist, a master bomb-maker and the leader of the most extreme splinter group of the Jemaah Islamiyah (JI) terror network blamed for the 2002 bombings of night-clubs in Bali which killed 202 people.

Investigators said they found an unexploded bomb and bomb-making materials in room 1808 of the Marriott, which they believe served as the attackers' operations centre.

They said the bombers stayed in the room for two nights before the attacks and disguised themselves as guests when they walked into crowded dining and meeting areas and detonated their suitcase devices.

The bombs -- brought fully assembled into the hotels despite airport-style security measures -- were packed with nails, ballbearings, nuts and bolts to maximise the carnage.

Police said they were "identical" to ones previously used in JI attacks, and were also the same as bombs found in a raid last week on an Islamic boarding school in Central Java, carried out as part of the hunt for Noordin.

President Susilo Bambang Yudhoyono, who was re-elected in a landslide on July 8, said the attack was an act of terror that would have "wide effects on our economy, trade, tourism and image in the eyes of the world".

Tourism is one of the biggest sources of foreign capital for Southeast Asia's biggest economy, which has avoided recession in the global financial crisis, but needs more foreign investment to maintain its growth trajectory.

Foreign ministers of the Association of Southeast Asian Nations (ASEAN) meeting in Bangkok Saturday denounced the bomb attacks and backed the Indonesian government's efforts to fight terrorism.

Indonesia's mainstream Muslim groups joined Yudhoyono and world leaders including US President Barack Obama in condemning the attacks, saying they could never be justified in Islamic teachings.