Mali's junta said on Friday it would resist any deployment of West African soldiers in the country and treat foreign forces sent there under a regional plan as "the enemy".
The comments came a day after regional bloc ECOWAS said it would send troops to Mali and Guinea-Bissau to tackle the aftermath of coups that, in the case of Mali, has left more than half the country in rebel hands.
"We will not accept any ECOWAS soldiers on our territory. This is non-negotiable. Any soldier who comes will be seen as the enemy," Bakary Mariko, a spokesman for Mali's CNRDRE junta, told Reuters by telephone.
Mariko accused ECOWAS - which called for elections within a year, ordered the military back to barracks and threatened military figures with sanctions if there was further meddling in politics - of going beyond its mandate.
He said the regional body need only provide Mali's army with logistics to help it defeat separatist and Islamists rebels now controlling the north: "We have the men."
While Guinea-Bissau has suffered from chronic instability, Mali had enjoyed 20 years of civilian rule before soldiers ousted the president on March 22 over complaints of his handling of a northern rebellion.
Taking advantage of the chaos after the Mali coup, a mix of separatist and Islamist rebels then seized the northern two-thirds of the country, carving out a zone experts fear is a haven for al Qaeda cells and international criminal gangs.
Mali has said it is ready for dialogue but with Mali's army in tatters after the lightening rebel advance, analysts and diplomats say it will take both time and outside support to put any form of pressure on the rebel forces.
The CNRDRE has officially handed power back to a civilian administration but arrests last week of top political and military figures involved in the previous government served as a reminder of the military's continued role in politics.
Tiebile Drame, a senior member of the anti-coup alliance of political parties, welcomed the ECOWAS decisions.
ECOWAS also called for elections in Guinea-Bissau within a year and threatened sanctions on military leaders if they failed to free political prisoners and restore civilian rule within 72 hours.
There was no immediate reaction from the junta in Guinea-Bissau but a Reuters journalist in the crumbling seaside capital, Bissau, said local army offers were meeting regional military chiefs at the Bissau airport on Friday.
Soldiers armed with machine guns and rocket launchers have also reinforced security at barracks
Few details have been made public but estimates of the size of the ECOWAS force in Mali have ranged from 3,000 to 5,000. A source at the bloc said it planned to send 638 men to Guinea-Bissau.
Gilles Yabi, West Africa analyst for the Brussels-based International Crisis Group, said West African forces would not be deployed without the consensus of local armies.
"There are constant discussions between them," he said.
"The risk for a confrontation is much higher in Bissau. They are hostile to foreign military interventions there. But even here, it will be negotiated with the military in Guinea Bissau."
ECOWAS soldiers there are due to be replacing Angolan forces who had been in the country but fell out with influential members of the army ahead of the coup.
West African leaders had been mulling support for Mali's army in its battle against northern rebels but plans were put on ice with the ouster of President Amadou Toumani Toure.
While there is still no clear mandate for the Mali mission, officials following the process say it is due first to be sent to Bamako to secure the democratic institutions and work with the army before options for tackling the north are considered.
However, a diplomat closely following the process warned that hundreds of millions of dollars in financing were still being sought and the gap between the political rhetoric and the reality of military planning was still wide.
"It is a long way from being anything practical or concrete," the diplomat said, asking not to be named.