The first batch of about 30,000 Indonesian troops due to withdraw from Aceh under a peace deal set sail from the tsunami-battered province Sunday, honoring a key concession in the accord to end one of Southeast Asia's longest-running wars. Some 800 chanting troops carrying bags and automatic weapons waved their helmets in the air as they marched aboard the warship, which departed for the city of Medan on Sumatra island, said Lt. Col. Eri Soetiko, a local military commander. A peace agreement signed last month in Finland between the government and Acehnese rebels is seen as Aceh's best chance in years to permanently end three decades of fighting that has killed nearly 15,000 people, according to a report of The Associated Press. Earlier this week, Free Aceh Movement, or GAM, rebels surrendered more than a quarter of their 840 weapons to EU and Southeast Asian peace monitors, with the remainder to be handed over by Dec. 31. Sunday's troop withdrawal marked the official beginning of the first phase in a gradual reduction of military and police units in the region that is linked to the decommissioning process. Around 1,000 troops left Aceh last month as a goodwill gesture. About 6,000 Indonesian troops are slated to leave in the next few weeks, and another 24,000 in the months that follow. Some 25,000 will remain behind. --SP 1301 Local Time 1001 GMT