Regional mediators urged Mali's junta leader on Wednesday to release politicians and high-ranking officers from the country's ousted government who have been detained by soldiers.

The arrests have raised concerns about whether Capt. Amadou Sanogo is in fact transferring powers to the new civilian interim government as promised under an agreement reached with the regional bloc ECOWAS.

Adama Bictogo, one of the ECOWAS mediators, said he hoped some of the detainees would be released in the next 48 hours.

"If they have evidence against these people they should make this known through the legal process," Bictogo said.

A number of senior politicians and high-ranking officers in Mali's security forces were arrested on Monday night and Tuesday by the junta despite the fact that junta leader has signed an agreement that is supposed to return Mali to constitutional rule.

Many of those arrested have close ties with the ousted president Amadou Toumani Toure.

In a statement late Tuesday the junta said that it carried out the arrests "on the strength of specific information." Ongoing police investigations will be handed over very soon so that judicial cases can be opened, the statement said.

"The material he has, we can't judge it, but according to Captain Sanogo these are things which could jeopardize the security of Mali," Bictogo said.

A group of soldiers and middle-ranking officers overthrew the government in Mali on March 21.

The coup leaders said they seized power because of the way the authorities were dealing with an uprising in the north of Mali. Rebels from the Tuareg ethnic group are seeking to create and independent state and Islamist groups want to see the introduction of Sharia law in the region.

After the coup the rebels took advantage of the disorder in the country to force Malian government forces out of the three major towns in the north, scoring a huge military victory.

Just three weeks after the coup, ECOWAS pressured coup leader Sanogo to sign an accord that was supposed to move the country back to civilian rule.

An interim president was sworn in last week and on Tuesday the president named a new prime minister, a former NASA scientist and Microsoft's former Africa chairman, Cheick Modibo Diarra.

But in statements since the agreement was signed, Sanogo has made clear that he plans for the junta to continue to play an important role in Malian politics.

The National Committee for the Reestablishment of Democracy and the Restoration of the State that he set up to run the country after the coup has yet to be dissolved, and Tuesday's statement referred to Sanogo as its president.

Sanogo says he will continue to monitor political institutions in the country until new elections can be held.

The European Union delegation in Mali issued a statement expressing concern about this week's arrests and calling for "an urgent clarification and their immediate release."

Both the EU and United States have suspended a large part of their aid to Mali and say they will not start disbursing funds again until the country returns to full civilian rule.