Malian men look at newspapers in Bamako.

Washington - The United States warned on Tuesday that Mali's political crisis was putting the territorial integrity of the large West African state at risk and called again on coup leaders to immediately return power to civilian authorities.

The State Department said the United States fully supported moves by the 15-member ECOWAS bloc of West African states to impose diplomatic, trade and financial sanctions on Mali's junta and urged armed rebels in the north of the country to cease military operations.

“Mali's territorial integrity is at stake, and its political institutions will be further weakened if Captain Amadou Sanogo and his supporters do not release their illegitimate grip on Mali and its people immediately,” State Department spokeswoman Victoria Nuland said.

Sanogo and his supporters have been hit with sanctions by both ECOWAS and the African Union since they seized power and deposed President Amadou Toumani Toure last month.

The United States, which sees Mali as an important partner in regional efforts to combat Islamic extremism, has suspended an estimated $60-70 million in aid to the country and Nuland said further steps were being discussed.

Nuland said the United States was increasingly concerned that advances by Tuareg separatist rebels in the north and the divisions within Mali's military were threatening the existence of Mali as a state.

“The United States urgently calls on all armed rebels in the north of Mali to cease military operations that compromise the Republic of Mali's territorial integrity,” Nuland said.

“As civilian leadership is restored in Mali, we also urge all armed rebels to engage in dialogue with the civilian leaders in Bamako to find a nonviolent path forward for national elections and peaceful coexistence.”

Nuland said the United States would strongly support a U.N. Security Council statement on Mali, which could come within days, as the first step toward possible broader punitive action.

Once one of the most stable democracies in West Africa, Mali has been in turmoil since the widely condemned March 22 coup that emboldened Tuareg rebels to seize half the country in their quest for a northern homeland.

They have been joined by Islamists bent on imposing sharia, Islamic law, across the whole of the moderate Muslim state, making it the latest security headache for a region battling al Qaeda agents and home-grown militant groups such as Nigeria's Boko Haram. ECOWAS decided on Monday to impose diplomatic, trade and financial sanctions on Mali's junta with immediate effect. ECOWAS military chiefs will discuss this week whether to “activate” a standby ECOWAS military force, but they gave no detail on when or how it would be deployed. - Reuters