In its report, 'The Military Mission in Darfur: Bridging the Gaps', the ICG said bold new action was urgently required to safeguard the inhabitants of Darfur, many of whom were still dying, being raped or facing indefinite displacement from their homes.
"The concept of African solutions for African problems has given western policymakers a convenient excuse to do no more than respond to AU requests," John Prendergast, special adviser to the ICG president, said in a statement.
"Darfur should not be treated solely as some capacity-building exercise for the emerging AU," he added.
The European Union (EU) and NATO were already offering significant financial and logistical support to the AU Mission in Sudan (AMIS) but, thus far, political sensitivities had kept non-African troops out of Darfur, the ICG noted.
"The AU has not yet pronounced itself on this statement," Justin Thundu, a public information officer for the AU, told IRIN on Wednesday from El Fasher, the capital of North Darfur State.
"The Sudanese government is not in favour of foreign, non-African, troops on its soil," he said, adding that it was up to Africans themselves to solve the conflict in Darfur.
However, the ICG called for more courageous thinking by the AU, NATO, the EU, the UN and the US to get adequate force levels, with an appropriate civilian protection mandate, on the ground in Darfur as quickly as possible.
"The current consensus to support a rough doubling of the AU force to 7,731 troops by the end of September 2005 under the existing mandate is an inadequate response to the crisis," James Terrie, the ICG's senior analyst for military and security issues, said.
The AMIS mandate had to be strengthened to prioritise civilian protection, the report noted, while a well-trained and equipped force of at least 12,000 to 15,000 was urgently needed on the ground.
Until the AU could perform the mission entirely with its own personnel, NATO should provide the number of troops needed to protect civilians by deploying its own bridging force.
Suliman Baldo, director of the ICG's Africa Program, observed: "It is disturbing that the daily death and suffering are becoming 'status quo' for some members of the international community," and added, "The situation has the potential to become another never-ending conflict, in which donors spend large sums feeding the displaced, but otherwise fail to protect civilians and to address the underlying political causes."
Sudanese government troops and militias allegedly allied to the government have fought in Darfur against rebels fighting to end a perceived marginalisation of and discrimination against the region's inhabitants by the state.
UN Secretary-General Kofi Annan estimated in his latest report on Darfur to the UN Security Council that conflict and drought in Darfur had affected more than 2.5 million people - over a third of the total population - including nearly 1.9 million internally displaced persons.
The AU had reached a total strength of 2,674 personnel, Annan added, consisting of a 1,732 troops for protection, 451 military observers, 460 civilian police and 31 international and Ceasefire Commission staff.
He noted that the AU mission in Darfur was effective in the areas where it had been deployed, and therefore needed strengthening to expand its presence to cover more of the vast and difficult terrain.
During his address at the African Union summit in Libya on Monday, Annan, called on the international community to increase its collective support to the AU in Darfur.