Secretary General Kofi Annan said today that he feared security was still inadequate in East Timor and that thousands of displaced people would be excluded from a crucial August vote on the territory's future.

The United Nations is responsible for organizing a ballot on Aug. 21 or Aug. 22 in the former Portuguese colony, now controlled by Indonesia. Voters will choose between independence and wide-ranging autonomy within Indonesia.

In a report to the Security Council, Annan said Indonesian police and military authorities have made progress in reining in the anti-independence militia responsible for most of the violence in East Timor. But he said "the activities of armed civilian groups continue to challenge the fundamental security, which all East Timorese deserve to participate fully in a credible consultation [balloting] process."

The violence has escalated since Indonesian President B. J. Habibie said in January that he would let East Timor go if voters rejected autonomy. Indonesia invaded the territory in 1975, an action not recognized internationally.

Many people have been driven from their homes or fled to avoid intimidation by the militia. Some observers estimate that as many as 60,000 people have been displaced, about 15 percent of the 400,000 eligible voters.

Annan, who postponed the balloting once before, must decide within three weeks whether voters can go the polls.