Sitting on the roof of his mud-walled compound on a hillside near Bamako, Amadou Maiga is dreaming of war. As the spokesman for the Gando Iso militia, Maiga says Malians cannot wait for international help to reclaim the north of his country from Islamist extremists. So they are preparing to take matters into their own hands.

"If we wait… we will give time for these terrorists to occupy the area because, according to the information, on the ground, more terrorists are coming," he said, from his home in Boulkassoumbugu, a suburb of the Malian capital.

The UN security council is expected to meet on Wednesday to discuss plans for a 3,300-strong regional Ecowas force to enter Mali, but it is unlikely any sort of military operation will begin before next September. Last week the UN secretary general, Ban Ki-moon, said military force may be required as a last resort, but stressed the importance of dialogue over war.

The militias are angry about the delay, and about the suggestion that Mali's government will offer the minority Tuareg separatists autonomy in exchange for joining the fight against al-Qaida-affiliated insurgents.

"There is nothing to negotiate with these criminals who killed people, who broke everything, who looted everything on the way," Maiga said.

Gando Iso, meaning sons of the land, is one of three militia groups unofficially supported by the government which have been training fighters at army military camps in Sevare, outside Mopti, 400 miles north of Bamako. Since the coup in March that left power precariously shared between a weak interim government and military junta leaders, the militias have gathered around 3,000 men and women who are willing to start a rebellion. "We don't want to work outside the law but if we have to do it… then we will take the decision to go," Maiga said.

The militias, many of which are accused of atrocities in earlier rebellions against the Tuareg, add another dangerous dimension to the crisis in the west African country. Gregory Mann, a professor at Columbia University specialising in the history of Mali, said there was a risk that militias would pursue their own objectives and "open the Pandora's box of the conflict; a set of grudges and grievances that have been difficult to contain in the past".

Ganda Iso is a successor to the Ganda Koy militia, whose name means masters of the land. They are disorganised, lack leadership and yearn for revenge against the minority Tuareg separatists, who have fought for more than 50 years demanding the independent state of Azawad. "Every day people are calling me, [saying] 'I want to go [to fight], I want to go,'" said Maiga.

Many civilians, who had been hoping for outside military intervention before the end of the year, now say they will take up arms to reclaim their country. "I am ready to go and fight myself," said a 40-year-old mother of three from Bamako.

"If I have to take a weapon and be in front of them and fight why should I not to do it? This is my country… I don't have anywhere else to go," she said.

She wiped tears from her face as she remembered the refugees she visited in the camps in neighbouring Niger. "We don't have oil, we don't have all this mineral wealth, but we are still human beings," she said.

More than 400,000 people have been forced to leave their homes in the north of the country since insurgents began moving through towns and villages looting and raping earlier this year. About 50,000 are in Bamako.

In a small hall in the centre of the city, 15 displaced women share a meal of jollof rice. Aramata Maiga, 62, explained how rebels looted her clothing shop in Gao, leaving only the chairs. "They are killing soldiers. They are killing citizens. They are killing everyone," she said.

Maiga has been sharing a room with her six children at a friend's house for eight months. She has no idea whether her home and business are still standing, but she's tired of "living in hell here in Bamako" and wants to go back to "fight to free my place".

At the chaotic Banke bus station in eastern Bamako, smoke-spewing buses leave for Gao and Timbuktu every day full of people returning to check on their property, livestock and, in some cases, stay behind in rebel-held areas – despite the risk.

"Many adults are returning to participate in the liberation in order to be there on D-day when the army returns," said Amadou Touré, a deputy mayor in Bamako responsible for registering the internally displaced people in his region.

Touré criticised the delayed military intervention. "It speaks of an international community who doesn't understand what's at stake at all," he said. He is still hopeful the Malian army, which left the country divided in two after abandoning its northern posts with barely a fight, will take action.

"It's simple. All we ask of the Malian army is to stick to their positions. They won't even need to fight – they just have to come and the people will help."

Analysts say the talk of a civilian rebellion is more than just bravado, and fear for the escalation in violence. Mann warns that Malians cannot rely on their army to support them. Ordered to retreat rather than fight, they lack equipment, money and clear leadership. "There's not a shred of evidence that the Malian army can actually perform," said the professor. "It's an army consistently weakened by internal fighting. My suspicion is that's why there's a delay in the international intervention."

Country in crisis

Mali was left rudderless in March when a coup by military officers, angry at the lack of action against northern Tuareg separatists, ousted President Amadou Toumani Touré ahead of the April elections. It paved the way for the Tuareg rebel group the Movement for the Liberation of Azawad (MNLA) to take advantage of the power vacuum and overthrow the weak Malian army. They seized control of the north, declaring the independent state of Azawad. They soon merged with the Ansar Dine rebel group but the partnership did not last; Mujao, Ansar Dine and al-Qaeia in the Islamic Maghreb (AQIM), armed groups linked to al-Qaida, turned on Tuareg MNLA and captured the northern cities of Timbuktu, Kidal and Gao, destroying Muslim shrines and enforcing strict forms of Sharia law. A new government has since been formed in Bamako, but military junta leaders still hold much of the power.