Under the peace deal only local troops will remain in Aceh province

The 3,353 soldiers will later leave Lhokseumawe port as troop numbers in Aceh are more than halved since August.

The rebels have already handed in their weapons and dissolved their armed wing.

In return for the cessation of violence the province, at the northern tip of the island of Sumatra, is being given more autonomy.

Tsunami catalyst

The BBC's Jakarta correspondent, Rachel Harvey, says it was the tsunami a year ago, which devastated large areas of Aceh province, which seems to have impelled both sides towards peace.

In the face of such widespread destruction and loss of life the two sides appeared no longer to have the stomach for the fight, our correspondent says.

KEY POINTS OF THE ACCORD Gam gives up all 840 of its weapons in four stages Government withdraws some 20,000 troops in four stages Disarmament and withdrawal to be complete by 31 December Government facilitates Aceh-based political parties Amnesty granted to Gam members Truth and reconciliation commission established Aceh monitoring mission set up by EU and Asean

More than 120 international aid organisations are now based in Aceh. Areas that were still no-go zones in the first few months after the tsunami are now opening up and the underlying threat that foreigners might be asked to leave has receded.

Hundreds of people gathered on the dockside at Lhokseumawe to witness the short ceremony marking the troop withdrawal.

The government troops are due to depart Aceh on three navy ships and two air force transport planes later.

Legal framework

In total, 24,000 soldiers will have been pulled out of the province since the peace agreement was signed in Finland in August.

Under the deal, the Indonesian government is committed to stationing no more than 14,700 soldiers and 9,100 police in Aceh, all of which are to be locals.

Before it was signed, Indonesia had more than 35,000 soldiers and 15,000 police in the province.

The deadline for the decommissioning of rebel weapons and withdrawal of Indonesian forces was the end of the year.

Former rebels have handed in more than 800 weapons to international monitors.

Under the terms of the agreement, Gam should be allowed to form a local political party, but that requires a change in the law which must be approved by parliament in Jakarta.

Our correspondent says that although there are still major challenges ahead, such as reintegrating former rebel fighters into civil society, the early stages of the peace process have gone remarkably smoothly.