The U.N. Security Council called for foreign troops to be quickly sent to Mali on Friday to contain a new offensive by radical Islamists who control the north of the country and are vowing to capture more terrain.
The fresh fighting in Mali has re-ignited Western fears that the al-Qaida-linked militants who currently control an area the size of France could capture even more territory and turn it into the same type of sanctuary that Afghanistan was under the Taliban.
Diplomats at the U.N. in New York said Mali's interim president Dioncounda Traore had appealed for help to Paris and U.N. chief Ban Ki-moon.
"It basically said: 'help -- France'," U.S. ambassador Susan Rice to the U.N. told reporters in describing Traore's letter.
French President Francois Hollande was expected to make a statement on the request during a meeting with the diplomatic corps in Paris at 1000 GMT.
Following an emergency meeting on Mali, the Security Council called for a "rapid deployment" of an agreed African force to the country and expressed "grave concern" at the capture of the town of Konna by "terrorists and extremists groups."
West Africa's regional bloc ECOWAS has agreed to deploy a force of up to 3,000 to help end the insurgency, but U.N. officials had warned that no boots were likely to hit the ground before September.
On the ground in Mali, however, witnesses told AFP that foreign troops and weapons had already begun arriving by transport plane on Thursday to bolster government forces in central Mali, but it was unclear what country they came from.
France had so far offered only logistical support to the regional force.
Witnesses told AFP of military aircraft landing with weapons and foreign soldiers at an army base in Sevare, just 60 kilometres (37 miles) from Konna.
One witness at the airport reported seeing weapons and soldiers leaving a C-160 military transport aircraft, adding: "Some of the men were white."
A Malian official, confirming the arrival of the military aircraft, said they included one plane from a European nation that left men and equipment at Sevare, but did not say which one.
Earlier Thursday Abdou Dardar of Ansar Dine, one of the groups occupying northern Mali, told AFP that Islamist fighters had taken Konna, northeast of the regional capital of Mopti.
"We almost entirely control the town (of Konna). Afterwards, we are going to continue" pushing south, Dardar said by phone. Witnesses told AFP that Malian troops were retreating.
The fall of Konna to the Islamists is a fresh blow to efforts to contain the radical armed Islamists.
Until now, they had stayed largely in Mali's vast arid north, where they took control nine months ago, taking advantage of a power vacuum after a coup in March.
Diplomats at the U.N. said about 1,200 Islamist fighters were now 20 kilometres (12.5 miles) from the key central town of Mopti, the gateway between rebel-held and government-held areas.
The deployment of the African force to capture the territory back from the Islamists has been delayed by political tensions in Bamako, where the coup leaders still hold considerable influence, doubts about the Malian army and funding for any military operation.
Rice said doubts had been raised in the emergency meeting late Thursday about the capability of the Malian army.
"One of the things we discussed is the extent to which the Malians are ready and willing to defend their own country," she said.