U.S. Assistant Secretary of State for African Affairs Jendayi Frazer met Sudanese President Omar al-Bashir Tuesday in Khartoum to deliver a message from President Bush on the Darfur conflict and the future of bilateral relations. The State Department says the Sudanese leader promised to send an envoy to Washington with his reply to the Bush message soon.

Assistant Secretary Frazer had to wait an extra day in Khartoum to get the meeting with President Bashir, who has been resisting pressure to upgrade the international peacekeeping presence in Darfur.

But officials here describe the nearly-two-hour session at the Sudanese president's private residence as a frank and fairly good discussion.

They said they remain optimistic that the Khartoum government, despite its stated objections, will accept the conversion of the African Union's observer mission into a full-scale United Nations peacekeeping operation.

The mandate for the seven thousand member A.U. force in Darfur expires at the end of September. Concerned about the prospect of worsening violence, the United States and Britain are pressing a draft U.N. Security Council resolution that would begin the transition to a blue-helmeted U.N. mission October 1.

Sudan has opposed the idea and even threatened to resist the introduction of U.N. troops with force. But a senior U.S. official who spoke to reporters here said in the meeting with Frazer Mr. Bashir did not, in his words, pound the table or reiterate bellicose statements opposing the transition.

The official said while negotiations with Sudan on Darfur have been difficult and protracted, he said there is forward movement and an expectation in Washington that Khartoum will ultimately accept the upgrade.

In Khartoum, meanwhile, a Sudanese government spokesman has repeated his government's opposition to replacing an African Union force in Darfur with U.N. peacekeepers.

At a news briefing, Deputy State Department Spokesman Tom Casey said there is a precedent, given that a United Nations mission is in Sudan monitoring implementation of last year's north-south peace accord. "There already is a United Nations force in Sudan. It is helping with the implementation of the north-south agreement. There already are international forces under African Union mandate in Darfur. The Darfur peace agreement specifically calls for a strengthening of those forces, and an expansion of them to be able to implement the agreement. And we think that it is not only very clearly in the interests of the international community but of the Sudanese themselves to see that there's a force sufficiently strong to be able to implement and help them implement, the Darfur peace agreement."

News reports from Khartoum said the Bush administration was offering to drop economic sanctions against Sudan and remove it from the U.S. list of state sponsors of terrorism if it agreed to accept U.N. peacekeepers.

Spokesman Casey refused to elaborate on the contents of the Bush message to Mr. Bashir but said that many things can occur in U.S.-Sudanese relations provided that progress is made in Darfur.

On a related issue, Casey said the Assistant Secretary raised with President al-Bashir the case of Chicago Tribune reporter Paul Salopek, arrested in Darfur earlier this month and accused of several offenses including espionage and entering Sudan without a visa.

A statement by Sudan's official news agency said President Bashir agreed to review the case from what was termed a humanitarian point of view.

The senior official who spoke here said U.S. diplomats have been given almost daily access to Salopek and that he has not been mistreated in custody. He said the spy charge against the Pulitzer Prize-winning correspondent is without foundation.