World powers pressed the Sudanese government Tuesday to accept the deployment of a U.N. peacekeeping force in Darfur to replace over-stretched African Union troops who have struggled to protect civilians from rebels and pro-government militias.

"Those who have signed the Darfur peace agreement are not implementing it, and there remain two important parties who continue to refuse to sign it," said European Union foreign policy chief Javier Solana. "Meanwhile, the people of Darfur continue a third year of suffering."

A daylong international conference on Sudan increased pressure on the two Darfur rebel groups who rejected the May peace deal and on the Sudanese government, which has refused to allow in a U.N. force to replace the AU peacekeepers.

CountryWatch: Sudan

Delegates, including U.N. Secretary-General Kofi Annan, African Union leader Alpha Oumar Konare and representatives from over 70 nations were united in urging for the U.N. force and calling for a halt to violence.

"This must stop immediately," Annan told the meeting. Annan warned that those frustrating peace efforts could face international sanctions.

The conference raised $200 million in fresh money to finance the 7,300-strong AU force over the coming months. Of that the United States provided $116 million, the European Commission gave $38 million and the Netherlands $25 million.

The figure raised was about half what the AU says it needs to keep the operation running until the end of the year, when the U.N. is hoping to take over mission. However, Konare told reporters that nations had assured him more money would come later to keep the operation afloat.

Officials expressed hope that the Sudanese government was edging toward dropping its opposition to a U.N. force with a stronger mandate and resources to replace the AU mission at the end of the year. "We are closer probably to having a change in that position," Solana said after talks with Sudanese Foreign Minister Lam Akol.

Since 2003, the Darfur conflict has killed some 200,000 and forced 2 million to flee their homes. The violence erupted when non-Arab tribes revolted against Sudan's Arab-led government, which is accused of responding by unleashing Arab militias known as Janjaweed who have been blamed for the worst atrocities.

"The current situation requires immediate action," Solana said. "Darfur is, by far, the worst conflict in Africa today."

The United Nations and African Union have both threatened targeted sanctions against those who obstruct peace efforts in Darfur. However AU Peace and Security Commissioner Said Djinnit acknowledged the organization lacked "mechanisms on the ground" that could verify cease-fire violations.

Although NATO and the EU have helped proved airlift and training, the AU force is thinly spread around remote eastern area roughly the size of France. In an appeal to the conference, aid agencies said the lack of manpower and equipment meant the African force could not maintain 24-hour patrols to protect villages and refugee camps.

"This lack of funding means patrols in and around camps are impossible or have been scaled back," said Denis Caillaux, secretary general of CARE international. "We are seeing people attacked, killed or raped as a result."

The U.S. is pushing for the handover to a U.N. force to be carried out as soon as September. "The key here is to move forward rapidly," said Jendayi Frazer, assistant secretary of state for African affairs.