Officials in Mali say they have seized 750kg of cocaine valued at $45m, after a two-hour gun battle on Thursday.The cocaine, one of the country's biggest drug hauls, was found near the town of Tin-Zaouatene in two four-wheel-drive vehicles.The smugglers abandoned the vehicles and reportedly fled over the Algerian border nearby, carrying their wounded.Correspondents say West Africa has become a major trafficking route for Colombian cocaine bound for Europe."The seizure took place... following a car chase and gun fight, or a battle, you could say, as they had military weapons," a senior Territorial Administration Ministry official told Reuters news agency."After two hours of fighting, the smugglers, who were driving three Algerian-registered off-roaders, abandoned two of them, loaded their wounded into the third vehicle and fled over the border," he said.The past year has seen large cocaine seizures in other West African countries including Ghana, Guinea Bissau, Senegal and Sierra Leone.