Secretary of State Colin Powell said Tuesday Sudanese authorities are not doing enough to improve security for refugees in the western Darfur region. He says he will consult with U.N. Secretary-General Kofi Annan this week on possible action by the Security Council.

Mr. Powell, who paid a dramatic visit to Sudan and Darfur earlier this month, is giving Sudanese authorities some credit for increasing humanitarian access to the troubled region.

But he says the performance of Sudanese authorities in controlling Arab militiamen blamed for massive human rights abuses in Darfur is far from what is needed, and he is raising the prospect of action against Khartoum in the U.N. Security Council.

Scorched-earth tactics against local rebels in Darfur by government-backed militias known as "Janjaweed" have killed thousands of people and driven an estimated one million from their homes, many of them into camps in neighboring Chad.

In a talk with reporters here, Mr. Powell said that since he visited the area, the situation has been "mixed," with Sudanese authorities allowing more aid supplies into the area and easing travel restrictions on relief workers.

But he said he made clear in telephone conversations Sunday with Sudanese Vice President Ali Osman Taha and Foreign Minister Mustafa Osman Ismail that actions taken by Sudan on the security front are insufficient. "While I took note of some marginal improvement on the humanitarian side, I also pointed out to them as clearly as I could that I, the President [Bush] and the international community remain completely dissatisfied with the security situation. Not enough is being done to break the hold of the Janjaweed. Rapes are still occurring. People do not feel safe leaving the camps, going out to forage for food. The situation remains very, very serious, and first and foremost, security has to be dealt with," he said.

Mr. Powell said he was having a dialogue with Secretary-General Annan on "what further action might be appropriate" on Darfur by the Security Council.

The United States has circulated a draft resolution there that would impose travel and financial sanctions against leaders of the Janjaweed; penalties could also later apply to Sudanese officials who are lending the militias material support.

The Secretary also said he expects to have initial reporting shortly from State Department officials who have been interviewing Darfur refugees as part of a U.S. study of whether the treatment of black African villagers by the militias meets the definition of genocide.

Such a finding could oblige the United States to pursue wide-ranging penalties against the perpetrators, though Mr. Powell said it "remains to be seen" how soon a judgment on the issue can be made.

Mr. Powell said the United States has been in touch with Darfur rebel leaders, trying to get them to resume peace talks with the Sudanese government broken off last week.

He said he had also spoken by phone Sunday with Nigerian President Olusegun Obasanjo on possible U.S. support for African Union troops who would protect the AU cease-fire monitoring mission already in the region.