Keith B. Richburg, Kupang – They fled here in abject retreat, packed onto trucks scrawled with the names of their militia gangs and bringing with them their assault rifles, machetes and dreams of revenge.

But as East Timor's militias have settled here, across the border in western Timor – now riding around the streets of Kupang in open-backed trucks and wearing their characteristic black T-shirts – they have brought their reign of terror and intimidation, this time against tens of thousands of displaced East Timorese living in sprawling refugee camps as virtual hostages, according to relief workers, human rights monitors and others.

There are now more than 200,000 East Timorese scattered throughout as many as three dozen camps – some of them in churches, government buildings and a stadium and some along the road with people living in tents and under tarps. Relief agencies say many, if not most, of those camps are controlled by the pro-Indonesian militias, who deny access to most Westerners. There have been repeated reports of militia members entering camps at night and taking away suspected supporters of independence for East Timor. Young men are also being forced to join the militias.

This is thought to be a regrouping, a swelling of the ranks, for a possible incursion into East Timor, where an Australian-led multinational peacekeeping force is gradually wresting control of the capital, Dili, from the armed gangs and departing Indonesian soldiers.

"Right now our job is to protect the refugees, but, like it or not, there will be war," said a 26-year-old militia member named Binto, who spoke at a camp located at a provincial sports stadium here. "We will return to East Timor, but we have to fight for it."

And relief agencies say they are alarmed that the Indonesian government has announced plans to begin relocating the refugees farther away from East Timor – part of what aid groups here fear could be a forced removal of people as a prelude to the eventual partitioning of East Timor.

"They've got between 150,000 and 200,000 people hostage here," a foreign relief worker said. "They're not refugees; they're hostages."

"What's happening here is horrible," he said, speaking on condition of anonymity. "They're burning houses on this side of the border. We hear reports of pregnant women being killed and their bellies split open. Boats leave with 'X' number of people and arrive with less." He added: "The militia and military – you can't make a difference anymore – are in control of this city. And the government can't do anything."

Khin Sandi Lwin, senior program coordinator for the UN Children's Fund (UNICEF) in Jakarta, just returned from a trip to the refugee camps at Atambua, near the border between East Timor and western Timor, and she said she saw militia members brandishing their automatic weapons inside the camps she visited. "This is a very strong militia-controlled area," she said. She was able to go into the camps only because she is Burmese; Westerners, and particularly "white faces," are generally not allowed.

She estimated that 127,000 refugees are living in the district around Atambua. Asked how many are there voluntarily, and how many are being held against their will, she said, "With the militia all around, we wouldn't want to ask them."

The New York-based Human Rights Watch also said in a statement: "Militias in West Timor are terrorizing the East Timorese, infiltrating the camps, and systematically attempting to identify and retaliate against independence supporters. They have also assaulted, 'disappeared,' and killed those attempting to aid and shelter refugees."

On August 30, nearly four-fifths of East Timorese defied militia intimidation and voted overwhelmingly to separate from Indonesia and become an independent state in a UN-backed referendum. But the anti-independence militias retaliated with a vengeance, engaging in murder and destruction that provoked intense international pressure on Indonesia to accept foreign peacekeepers in East Timor.

As they embarked on their rampage, the militias were seen herding thousands of East Timorese toward the border. Relief workers said they fear that many – particularly young men, anyone associated with the United Nations or working for foreigners, or anyone suspected of being an independence supporter – may have been executed along the way.

The International Committee of the Red Cross, for example, had about 70 East Timorese staff members in Dili. When militiamen raided the Red Cross compound, the expatriate staffers were loaded onto a truck and eventually taken to the airport to leave. About 2,000 refugees, and some staff members at the compound, were last seen being marched along the beach. Today, Red Cross officials said only 11 of their local staff members have arrived in western Timor; the others are missing.

Not all of the refugees here are considered "hostages." Some are the relocated families of military personnel, others the families of the militias. They are kept in military camps, like the Noelbaki camp about nine miles from here, where most of the men wear military uniforms.

The militia campaign of terror has extended beyond western Timor, and is said to reach as far away as Bali, and even Jakarta, where suspected independence supporters have received death threats and are being hunted down. Some East Timorese university students, and Red Cross staff members, have been moved several times because of death threats, with some being relocated to Darwin, in northern Australia.

"There's militia in Jakarta, there's militia in Surabaya," said an aid worker here. "They know who they're looking for. They have names." "The carefully-planned campaign of violence and terror carried out by the Indonesian security forces and their militia surrogates in East Timor and in west Timor over the past several weeks has spread throughout Indonesia," said the Atlanta-based Carter Center, which sent monitors to observe the East Timor referendum and still has observers scattered around the archipelago.

"Armed militias [continue] to harass and terrorize refugees from East Timor who have taken refuge in Bali and several cities on the island of Java, including the Indonesian capital of Jakarta," the center said in a report.

No one seems certain of the motive for holding tens of thousands of people hostage. But some relief groups and human rights officials have suggested the militias may have been trying to empty East Timor of its pro-independence population as a prelude to demanding that the western half of the territory be allowed to remain a part of Indonesia. The western half, with its coffee plantations, is the most economically viable part of otherwise poor East Timor, and many prominent Indonesians are said to have business links there.

An aerial survey of the western side of East Timor done Thursday by the United Nations found "very few people living there," according to David Wimhurst, a UN spokesman in Darwin.

The government has announced plans to relocate as many as 100,000 East Timor refugees away from the border areas and into semi-permanent settlements elsewhere in East Timor, as well as on neighboring islands.

[Special correspondent Atika Shubert in Kupang contributed to this report.]