A detained Malaysian militant, allegedly trained as a pilot by Al-Qaeda to crash a plane into a Los Angeles skyscraper, remains a security threat, a former security official said today.

"He is still a threat. He has to be kept inside," the former intelligence official told AFP on condition of anonymity.

His comments were in response to calls from rights groups and family members to free engineer Zaini Zakaria who was among three men allegedly trained by Osama bin Laden's Al-Qaeda network to take part in the attack.

Zaini has been detained by Malaysian police since December 2002 under the country's tough Internal Security Act that permits two-year detention periods that can be renewed indefinitely.

The ex-official has said that Zaini was sent to train in the movement's camps in Afghanistan in 1999.

It was in these camps that he met the network's top people, including Hambali, a leader of the Al-Qaeda affiliate Jemaah Islamiyah (JI).

Zaini then returned to Malaysia and obtained a licence to fly a small plane, and was to have started learning how to fly a jet in Australia.

"That part of the plan never materialised. Malaysian authorities managed to detain him in 2002," the ex-official said.

He said he feared Zaini could influence other people if he was freed.

Family upset

Chang Lih Kang, spokesman of rights group Voice of the Malaysian People (Suaram) said the Malaysian government should free Zaini or charge him in an open court.

"We are saying Zaini is innocent. Free him or charge him in court," he told AFP adding that his family was upset with the terror allegations.

"The family is upset that Zaini is being branded as a militant," he said.

But Zaini has told Malaysian officials he pulled out of the Al-Qaeda plan after witnessing the September 11 attacks in 2001.

US President George W Bush has said Khalid Sheikh Mohammed, thought to be one of the masterminds of the 2001 attacks, planned to hijack a plane and fly into LA's tallest building, the 310-metre (1,017-foot) US Bank Tower, also known as Library Tower.

Bush said that instead of using Arab hijackers, as in the attacks on the World Trade Centre and the Pentagon, the plot called for "young men from Southeast Asia whom he believed would not arouse as much suspicion."

Malaysia is holding over 100 people under the Internal Security Act, more than 80 of whom alleged Islamic militants.