* Mali loses key government foothold in border region
* Attempts to resupply Tessalit had failed, soldiers fled
* Tuareg fighters seeking to carve out desert homeland
BAMAKO, March 11 (Reuters) - Tuareg rebels seeking to carve out a desert homeland in Mali's north have taken control of the key garrison town of Tessalit following a weeks-long siege, rebel and military sources said on Sunday.
Malian army units defending the town, one of the government's few footholds in the area, fled overnight towards the Algerian border after attempts by the military to resupply them were beaten back, the sources said.
"This strategic base and Tessalit International Airport are under the control of the National Movement for the Liberation of Azawad," spokesman for the MNLA rebel group, Bakaye Ag Hamed Ahamed, said in a statement emailed to Reuters.
Two Malian military officials, speaking to Reuters by telephone on condition of anonymity, confirmed the rebels now controlled Tessalit after soldiers had retreated.
One of the military sources said commanders in Tessalit had warned Mali's military they would be forced to withdraw if supplies and reinforcements did not arrive by Saturday, after weeks of fending off the well-armed rebels.
"Around 1900 GMT (on Saturday), the military shut down their radio communications and headed to the town of Bordj Elmoktar (in Algeria)," he said.
"During their retreat, some Malian army soldiers were taken prisoner by the rebels of MNLA."
The MNLA said it also captured some armored vehicles, troop carriers and heavy and light weapons from the base.
Mali's loss of the base leaves government forces with little presence in the remote border region, a major setback as the rebels seek to establish control of the vast north.
The MNLA have been bolstered by heavily armed Malian Tuareg returning from fighting alongside pro-Gaddafi forces in Libya. The clashes have added a new layer of insecurity to a zone awash with smugglers and plagued by fighters linked to al Qaeda and is expected to complicate presidential elections due in April.
Dozens of people have been reported killed and more than 100,000 people have fled their homes since the rebels launched their offensive in mid-January.
The government has repeated charges that the MNLA rebels were fighting alongside drug dealers, al Qaeda factions and other Islamists. The rebels have denied the allegations.
A spokesman for Mali's government was not immediately available on Sunday.
A U.S. embassy spokeswoman in Bamako said in early March a U.S. aircraft had supplied food and water to Tessalit on February 14 but no further action had been taken. (Reporting by Adama Diarra; Additional reporting by David Lewis; Writing by Richard Valdmanis; Editing by Sophie Hares)