Islamist rebels will attack Mali's capital city if international military intervention is launched to regain control of the country's north, a senior member of an insurgent group closely linked to al-Qaida has told the Guardian .

Oumar Ould Hamaha, head of security for the Movement for Tawhid and Jihad in West Africa (Mujao) claimed that rebels have recruited thousands of new fighters and warned that intervention would galvanise the international jihadist movement.

"If an international or Malian military force attacks us, we will take Bamako in 24 hours," Hamaha said in a telephone interview. "The international community is slow to strike because it knows that if it does, it will spark a worldwide jihad.

"Plans for a military intervention do not diminish in any way our determination to promote jihad," Hamaha added. "We are convinced that with the help of Allah we will defeat any army coming. We have the support of the local people, and we have people from all parts of Africa coming to join us. We are ready to die."

The defiant rhetoric from Mujao – which together with al-Qaida in the Islamic Maghreb (AQIM) and Ansar Dine control the northern two-thirds of Mali, including military bases, airports and several towns – came as US secretary of state Hillary Clinton arrived in Algeria to rally support for intervention.

Earlier this month, the UN security council adopted a resolution underscoring its "readiness" to send an international force to drive Islamists out of northern Mali, setting a deadline at the end of next month for a firm plan for military action. Mali is working on plans involving troops from the Mali army and west Africa regional bloc ECOWAS, with training, logistics and intelligence support from France, the US and other countries.

But military action would probably require the support of Algeria, which initially opposed intervention. The country shares an 2,000km desert border with Mali – seen as a key route for illicit trade of arms and drugs in and out of Mali – while many insurgents fighting in northern Mali are reported to be of Algerian origin.

"There is a strong recognition that Algeria has to be a central part of the solution," said a US official, who added that the situation in northern Mali would be a "central focus" of Clinton's talks with the Algerian president, Abdelaziz Bouteflika.

The role of the US in combatting AQIM in northern Mali has been a source of controversy in recent weeks. Hamaha told the Guardian the Mujao was aware that US surveillance drones were operating regularly in the region already, and that the unmanned aircraft were having the effect of encouraging support for the Islamist cause in northern Mali.

"We see drones passing overhead all the time. This is not something we take seriously – we are not afraid of drones. On the contrary, by trying to intimidate us, the west is only sharpening the sword we will use against it."

Experts said rebel threats to attack southern parts of Mali could not be discounted. "I think the claims about Bamako are mostly posturing, but we cannot rule out the possibility of attacks outside of northern Mali," said Andrew Lebovich, a researcher on the Sahel and north Africa. "AQIM and Mujao have operated beyond the confines of northern Mali in the past, and these groups do have the capability to stage attacks elsewhere, although it would be difficult given the attention on these groups at the moment."

Hamaha said that there were no prospects of negotiation.

"We don't recognise any government in Bamako," Hamaha added. "The minister of defence called me to talk about negotiating towards a secular state. I told him it's sharia or the sword. No sharia, no dialogue. Our mission is straight. There is no negotiation to be had."

The Mali government refused to comment on the status of its negotiations with the groups, but the head of the EU delegation in Mali said that negotiations were still considered a potential alternative to conflict in northern Mali.

"No one is talking about military intervention as if it is the end of the track," said Bertrand Soret, EU chargéd'affaires in Mali. "We have been pushing for dual track approach – negotiations and building up military force. We are not recommending talking to terrorists, but we are pushing for the Malian authorities to deal with some of the groups from their side."