The junta that seized power in a coup in Mali last month announced that it had released 22 people whose arrests earlier this week had prompted international criticism.
The arrest of senior politicians and military personnel took place even though Mali now has a civilian president and prime minister.
Those opposed to the coup said the arrests showed that the soldiers who carried out the coup were not ready to hand over power.
In a statement, Colonel Diamou Keita said he was informing "national and international public opinion" of the detainees' release.
"However, the parties involved will remain at the disposal of the authorities concerned for the purposes of the investigation," said Col Keita.
Both the president and the prime minister of Mali had called for the soldiers to respect the normal legal procedures if they had any evidence that the people detained had committed crimes.
The regional body Ecowas, the European Union and UN had all called for those detained to be released immediately.
"There is a danger that actions like this could undermine the authority of the prime minister who has just been nominated," said Richard Zink the head of the European Union delegation in Mali.
"It seems that the pressure from Ecowas and Mali's other international partners has worked this time."
Late on Wednesday, Col Keita had announced on national television that the 22 people had been arrested after stockpiles of weapons were found in various homes.
Col Keita said the weapons did not belong to Mali's military and that the country is facing "a new threat".
Among the detainees are one of overthrown President Amadou Toumani Toure's former prime ministers, the general in charge of Mr Toure's personal military protection and the country's former defence minister.
The president of one of Mali's biggest political parties was also arrested. Soumaila Cisse was one the front-runners for the presidential election set for April 29 that was derailed by the coup.
Amid the post-coup political upheaval, separatist rebels in northern Mali declared an independent state that is larger than France.
The power vacuum also has allowed an Islamic faction that wants to impose Shariah law in the area to flourish.