BAMAKO, Mali -- Soldiers arrested Mali's prime minister and forced him to resign before dawn on Tuesday, showing that the military remains the real power in this troubled West Africa nation, even though officers made a show of handing back authority to a civilian-led government after a coup in March.

The development underscores the deep volatility at the heart of the once-stable nation of Mali, and reveals the threat that its military poses. The events come at the very moment that the United Nations is considering backing a military intervention, which would use these same soldiers to spearhead an operation to take back Mali's north from Islamic extremists.

Prime Minister Cheikh Modibo Diarra, dressed in a dark suit, his forehead glistening with sweat, went on state TV at 4 a.m. to announce his resignation, hours after soldiers stormed his house and forced him into their vehicle.

"Our country is living through a period of crisis. Men and women who are worried about the future of our nation are hoping for peace," he said on television. "It's for this reason that I, Cheikh Modibo Diarra, am resigning along with my entire government on this day, Tuesday, Dec. 11, 2012. I apologize before the entire population of Mali."

After they taped his resignation, the soldiers allowed the 60-year-old to return to his residence Tuesday, where he is now under house arrest, said a spokesman for the junta, Bakary Mariko.

The shake-up in Bamako is already looking like it might endanger plans for a military intervention, which is being discussed this week by the U.N. The African Union agreed to a plan calling for 3,300 African troops to be deployed to Mali to help the Malian military take back its northern territory, which fell to al-Qaida-linked rebels in the chaos following the military-led March 21 coup in the capital.

Already the United States and France are at odds on the best way forward, with France pushing for a quick intervention in order to expel the extremists, while the U.S. is arguing for a more gradual approach, starting with negotiations.

Diarra's forced resignation and arrest makes Western countries wary of getting involved in a military incursion, Germany's Foreign Minister Guido Westerwelle, a member of the U.N. Security Council, warned Tuesday.

"One thing is clear: Our offers of help come with the condition that the process of restoring constitutional order in Mali be conducted credibly," Westerwelle said in a statement. "And it is only that way that the crisis in northern Mali can be resolved ... All the country's political leaders must now act responsibly so that Mali returns to stability."

Despite the events, however, a European Union military training session aimed at giving the Malian military the ability to oust the Islamic extremists is proceeding as planned, said Michael Mann, a spokesman for EU foreign policy chief Catherine Ashton.

Hours before he was forced to tape his resignation statement, Mali's prime minister was arrested at around 10 p.m. Monday by the military at his home, forced into a car and driven to the Kati military camp, the sprawling base where the March 21 coup was launched. Two security officials, including a police officer and an intelligence agent, confirmed that coup leader Capt. Amadou Haya Sanogo had ordered the prime minister's arrest.

At the moment of his arrest, the aging civilian leader was getting ready to leave for the airport for a medical trip to Paris, said the police officer who asked for anonymity because he was not authorized to speak to the press.

"The plane that was to take the prime minister to France was on the point of departure," said the policeman who was on duty at the airport at the moment of the incident. "It was stopped by people from the Yerewoloton group who invaded the airport," he said, naming the civilian organization believed to be backed by Sanogo.

This same group in May invaded the presidential palace, as soldiers looked on, and beat the country's interim president Dioncounda Traore, until he lost consciousness. That incident brought the international community down like a hammer on the head of Mali's junta.

Sanogo signed a lengthy accord, agreeing to step down, and retreated from public life, although there were signs that the military still called the shots in Bamako.

Junta spokesman Bakary Mariko acknowledged that soldiers allied with Sanogo arrested the prime minister, and are now holding him under house arrest. Mariko said that Diarra was "not getting along" with either the interim president, or the coup leader Sanogo.

"He says he's going to Paris for medical tests ... but we know better and realize that he is trying to flee in order to go and create a blockage in the Mali situation ....It's the reason why Mali's army has taken things into their own hands and told Cheikh Modibo Diarra to resign for the good of Mali," Mariko said.

Human Rights Watch's senior researcher for West Africa, Corinne Dufka, condemned the military's intervention, saying it fits with the pattern of abuse by the soldiers ever since the coup eight months ago.

"They've arrested, beaten and intimidated journalists; tortured and disappeared military rivals; and now, apparently, arbitrarily detained the prime minister. None of these incidents have been investigated and those responsible appear to have been emboldened by the shameful lack of accountability," said Dufka.

Diarra, an astrophysicist who previously led one of NASA's Mars exploration education programs, was initially seen as in-step with Sanogo. Critics lambasted him for frequently driving to the Kati barracks to see the coup leader, long after Sanogo was supposed to have handed power to civilians. In recent weeks though, Diarra has taken stances that sometimes conflict with Sanogo.

Bamako remained calm on Tuesday, as the capital awoke to what some are calling a "mini-coup." People went about their daily lives, but with a sense of deep disappointment in this nation once held up as a model democracy in Africa.

Aboubacrine Assadek Ag Hamahady, a professor at Bamako's university said: "I really am struggling to understand -- so if the prime minister is not doing his job properly, it's up to the junta to come and arrests him? So what's the purpose of having a President? ... Based on what law, on what legal text can the junta justify this arrest?"