A new report says the peace agreement signed more than a year ago to end a lengthy civil war in Sudan is showing signs of strain and there is a real risk of renewed conflict if the accord is not implemented soon.

The latest report on Sudan by the International Crisis Group, a non-governmental organization that analyzes conflict zones, says one of Africa's longest and deadliest civil wars could re-ignite if what is called the Comprehensive Peace Agreement is not implemented in good faith.

The agreement, signed in January of 2005, was designed to end the 21-year armed struggle between government forces in the mostly Arab Muslim north and rebels in the animist and Christian south that killed an estimated two-million people.

The report charges that the ruling National Congress Party has not carried out important aspects of the peace deal, and the former rebels of the Sudan People's Liberation Movement are too weak and disorganized.

The agreement created a new north-south Government of National Unity in Sudan, but the report suggests the arrangement is barely functioning.

The International Crisis Group's senior analyst for Sudan, David Mozersky, said in a telephone interview from his office in Nairobi that the peace deal is very important to regional stability. "If the agreement were to fall apart and war to resume in Sudan, it would have devastating consequences for the whole region. This peace agreement is critical to stability in the Horn of Africa," he said.

The report says the government in Khartoum has abandoned its strategy for a political partnership with the Sudan People's Liberation Movement.

It says the southern group has not yet reorganized the rebels into a professional army, and there are extended delays in paying its troops and civil servants.

David Mozersky of the Crisis Group says the international community needs to be more involved in making sure the peace deal is implemented. "That international engagement which was so critical to attaining the agreement has largely dissipated since the agreement was signed. So there is a lot of involvement today, international involvement, on the development side, but very little involvement on the political side," he said.

The north-south unity government has urged the United States to drop sanctions against Sudan imposed in 1997, saying the penalties are hurting efforts to improve the country's economy.

U.S. diplomats say the sanctions will remain in place because of the continuing violence between rebels and pro-government militias in Sudan's western Darfur region.