In the first attack against the growing United Nations presence in the Indonesian territory of East Timor, more than 100 anti-independence militiamen surrounded a newly opened U.N. outpost in the town of Maliana early today, showering the building with stones and injuring a diplomat from South Africa.

At least a dozen Timorese were also injured in the attack, which took place near the West Timor border, in an area known to be a stronghold of militia who oppose independence from Indonesia. The injured Timorese were among a large group who had run inside the U.N. building seeking refuge from the attack, said David Wimhurst, a U.N. spokesman in Dili, the East Timorese capital.

"This is the first attack on one of our offices," Wimhurst said, adding that the mission "was considerably damaged."

The attack -- which could jeopardize the entire peace plan for East Timor -- came as faction leaders were meeting in Jakarta, trying to find a way to stem the violence that has rocked the territory since Indonesia announced this year that it would allow a vote on independence.

[On Wednesday, U.N. special envoy Jamsheed Marker said the U.N. would not be scared off by the attack, Reuters news agency reported. "It's definitely an aberration," Marker said as he left the Jakarta talks, which were sponsored by the Roman Catholic Church. "We are here to do a job, and we won't be chased away."]

Since the announcement of the referendum, there has been an escalation of violence in East Timor by armed militia groups, backed by the Indonesian military, that have tried to intimidate the population into rejecting independence. The militias back Timor's further incorporation into Indonesia under a plan that would give the territory broad autonomy. Indonesia has occupied East Timor since 1975.

Since the militias began their campaign, dozens of people have been killed and independence supporters have been forced into hiding or exile. Thousands of villagers have been herded out of their homes and are being kept in conditions that human rights workers have likened to concentration camps, as the militias try to create a captive population that will vote for autonomy and keep East Timor part of Indonesia.

The U.N. mission is in East Timor to oversee preparations for the referendum, and U.N. police officers were sent to guarantee that security conditions improve enough to allow the balloting. But under the agreement reached with Indonesia, the U.N. police are unarmed and must rely on Indonesian police for protection.