Dili, Indonesia - The United Nations completed voter registration Friday for East Timor's independence referendum, signing up far more voters than expected despite sporadic violence in the Indonesian province. Attacks by anti-independence militias in recent days injured four people and shut down four out of 200 registration centers.

UN officials said voter rolls for the Aug. 30 ballot could top 450,000, exceeding their most optimistic projections. ``Security remains precarious in many trouble spots, especially in the eastern part of the territory,'' said U.N. spokesman Yasuhiro Ueki. ``The fact that some militias are acting with impunity and the Indonesian police force is not able to control them is a cause for serious concern.''

Militiamen on Friday attacked and injured a villager outside a registration center in Same, about 60 miles south of Dili. The U.N. Assistance Mission in East Timor suspended its activities there. On Thursday, four registration centers in the western Bobonaro region were temporarily closed after two separate attacks. Three U.N. staff members were slightly injured, Ueki said. One of the centers remained shut Friday after two truckloads of militia members made more threats, Ueki said. Some registration centers might reopen for a few hours on Saturday to process would-be voters who missed Friday's deadline, Ueki said.

The ballot will give East Timorese the choice between full independence and remaining part of Indonesia as a self-governing region. Pro- and anti-independence forces are tentatively scheduled to begin their political campaigns on Wednesday. Indonesian Foreign Minister Ali Alatas is expected to visit East Timor on Saturday to meet UNAMET chief Ian Martin.

East Timor, a former Portuguese colony some 1,200 miles east of Jakarta, has been wracked by guerrilla warfare, civil unrest and human rights abuses since it was occupied by Indonesia in 1975. UNAMET has postponed the ballot date twice because of violence and attacks against its staff.