Sudan was the subject of a congressional hearing Tuesday on Capitol Hill as lawmakers raised question about Bush administration steps to end violence in Sudan's western region of Darfur, and help move the Sudan peace agreement forward. The hearing took place as Sudan's First Vice President Salva Kiir traveled to Washington for talks with U.S. officials.

The visit comes amid concern that the Khartoum government, and Sudan People's Liberation Movement (SPLM), are not making enough progress solidifying their peace accord, and that Khartoum hasn't taken steps to end violence in Darfur once and for all.

"Failure to resolve the Darfur situation could help unravel the peace between the North and the South," said Republican Congressman Chris Smith, chairman of the House Subcommittee on Africa and Global Human Rights. "Certainly that peace agreement faces its own challenges from a National Congress Party that seems to want an agreement in name only, and from a SPLM struggling to regain its footing after the death of its longtime leader."

The Comprehensive Peace Agreement (CPA) signed earlier this year created a Government of National Unity in Khartoum. Salva Kiir assuming the position of First Vice President after southern rebel leader John Garang was killed in a helicopter crash.

U.S Assistant Secretary of State for African Affairs Jendayi Frazer, says the agreement and the situation in Darfur are linked.

"Implementation of the CPA is crucial to ending the violence in Darfur," she said. "Moreover, without progress in Darfur, there is a real danger for the violence to spill over into other areas of Sudan. The bottom line is [that] the CPA is applicable in many respects to all areas of Sudan and is designed to share power and wealth between the center and periphery areas, the key root of the conflict in all parts of Sudan.

Assistant Secretary Frazer reported progress in forming key commissions under the new Sudan unity government. She listed redeployment of government troops from [the southern city of] Juba as one urgent matter, along with a political solution to end violence in Darfur.

Mr. Salva Kiir's talks in Washington are focusing on requests by Khartoum to lift eight-year-old sanctions against Sudan, and the question of removing Sudan from the U.S. State Department's list of countries supporting terrorism.

But members of Congress want assurances that there will be no easing of U.S. pressure on President Bashir, or any steps toward normalizing relations before violence ends in Darfur.

Lawmakers are angry not only over apparent ongoing support by Khartoum for Arab militias, but continuing restrictions on humanitarian efforts, and the refusal of the Bashir government to allow only 35 of more than 100 personnel carriers into the country for use by African Union peacekeeping troops.

"In dealing with this government, we ought to have a policy that tells them either they have to make the policy work or we ought to come down with some serious policy against them," said Democratic Congressman Donald Payne. "This business about we let a few in, and we may let them out, some of our humanitarian groups now have not been issued anymore permits to come in, Doctors Without Borders were given a hard time because they were outspoken, it just continues as people die, every day."

In a letter to Secretary of State Condoleeza Rice, 105 Democrat and Republican House members say the Bush administration has not taken strong enough measures to end violence in Darfur.

They express concern about what they call an apparent softening of U.S. policy toward the Government of Sudan, citing among other things upgrading of Sudan's rating in a U.S. report on human trafficking.

Lawmakers are also upset with a Bush administration decision to issue a waiver to allow a U.S. lobbyist to represent Bashir government interests in Washington.

The letter asks Secretary Rice for clarification of what the signatories call actions that appear to be inconsistent with the standing U.S. position that atrocities in Darfur constitute genocide.

Darfur and the status of the North-South peace agreement, which is the subject of talks underway in Abuja, Nigeria, will be key items on the agenda of Deputy Secretary of State Robert Zoellick when he visits Sudan next week.