The Ministry of Home Affairs said some of the 21 Singaporeans arrested last month conducted surveillance of Changi Airport, a US navy vessel, chemical plants, water reservoirs and the Ministry of Defence headquarters as potential targets.

The city state, which hosts a US navy logistics base and numerous American multinational companies, has also detained 12 Singaporeans and one Malaysian without trial since December for plotting to blow up the US embassy and other targets.

Singapore and Malaysia, which is holding dozens of people under its own internal security laws, say the suspects are part of Jemaah Islamiah -- a group believed to be seeking an Islamic state linking Indonesia, Malaysia and the southern Philippines.

They also say Jemaah Islamiah has links to the al Qaeda network that is accused of carrying out the September 11 attacks on the World Trade Center and the Pentagon.

"The aim was to create a situation in Malaysia and Singapore conducive to overthrowing the Malaysian government and making Malaysia an Islamic state," the ministry said in a statement.

"The attacks on key Singapore installations would be portrayed as acts of aggression by the Malaysian government, thereby generating animosity and distrust between Malaysia and Singapore."

Singapore, whose population is about three-quarters ethnic Chinese, split from Muslim but secular Malaysia in 1965 after a brief union between the two former British colonies.

The ministry said alleged Jemaah Islamiah leader Riduan Isamudin, an Indonesian Muslim preacher also known as Hambali, "aimed to stir up ethnic strife by playing up a 'Chinese Singapore' threatening Malays/Muslims in Malaysia".

TRAINING WITH AL QAEDA

All but two of the 21 men were members of Jemaah Islamiah (JI), the ministry said, adding the others had ties to the Moro Islamic Liberation Front, a Muslim rebel group in the mainly Catholic Philippines.

"At least three of these JI members have undergone military training at al Qaeda facilities in Afghanistan while one attended several training stints with the MILF in Mindanao," it said.

Eighteen of the 21 men have been detained for two years. Three who "did not participate in terrorism-related activities" have been restricted from travelling overseas and having contact with militant groups, the ministry said.

The suspects held without trial include a taxi driver, a butcher, a used car salesman and a part-time foot reflexologist.

"With these present arrests, the Singapore JI network has been severely disrupted," the ministry said, adding investigations would continue to prevent remnants from re-grouping or linking up with members abroad.

Home Affairs Minister Wong Kang Seng said on Wednesday he could not rule out more arrests.

The latest detentions in Singapore are likely to result in more diplomatic pressure on Indonesia, the world's most populous Muslim nation, which has been criticised as Southeast Asia's weakest link in the war on terror.

Organisations representing Singapore's Muslim minority have distanced themselves from Islamic fundamentalism, but one has criticised the city state's use of detention without trial.

"The unlawful arrests cannot be challenged in court because (they were) made by the Internal Security Department," the Fateha group said on its Web site. "It does not need to show evidence."

According to an AFP report the government said the suspected terrorists wanted to create another "Ambon", referring to the Indonesian city where more than 5000 people have been killed in religious violence since 1999.

"The aim was to create a situation in Malaysia and Singapore conducive to overthowing the Malaysian government and making Malaysia an Islamic state.

"The attacks on key Singapore installations would be portrayed as acts of aggression by the Malaysian government, thereby generating animosity and distrust between Malaysia and Singapore."

The government said the regional JI leader, an Indonesian known as Hambali, "aimed to stir up ethnic strife by playing up 'Chinese Singapore' threatening Malays/Muslims in Malaysia," the report said.

"He hoped that this would create a situation which would make Muslims respond to calls for Jihad, and turn Malaysia and Singapore into another 'Ambon'."

The targets in Singapore included vital water supply pipelines from Malaysia, Changi airport, Jurong Island where Singapore's oil refineries and petrochemical plants are based, and the ministry of defence headquarters.

Other targets included a US vessel at the Changi naval base, and a pub which they belived to be frequented by US military personnel, the government said.

"So far, none of these efforts are known to have led to any fully developed or finalised plan for attack," the report said.

It detailed the names of JI operatives who were to be involved in each operation, as well as details photographs, maps and other evidence found by Internal Security Department officers.

Hambali, also known as Riduan Isamuddin, is described as being in charge of the JI in Malaysia and Singapore, and having direct links to a key lieutenant in Osama bin Laden's al-Qaeda network.

Earlier Singapore reports named Hambali as the go-between who arranged for Singaporeans to train at al-Qaeda camps.

The JI members in affluent Singapore were important to the organisation as a source of funds to fund cells, purchase equipment and send JI members abroad for military training.

Many were sent to al-Qaeda camps in Afghanistan, with one attending several training stints with the Moro Islamic Liberation Front (MILF), the largest Muslim separatist force in the Philippines, the report said.

Of the 21 arrested last month, 18 are being held under the harsh Internal Security Act, which allows for detention without trial.

The other three, "who did not participate in terrorism related activities" are under restriction orders that forbid them leaving the country or "having any contact with any militant organisation", the government said.

The 13 JI members, detained in December and said to be planning to blow up the US embassy and other Western targets, are also being held in indefinite detention.

An earlier report on their arrests said they they had all admitted "terrorism-related" activity and were tied to a plot that would have had catastrophic consequences if they had pulled it off.

A video tape of their likely targets was found in the Afghanistan home of Mohammed Atef, the al-Qaeda military adviser who was reportedly killed when his house was bombed by US forces last November.

In its latest report, the government said the additional 21 arrests had "severely disrupted" the Singapore JI network, "however, the threat from regional JI elements remains" and investigations were continuing.

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