John Aglionby, Jakarta – Indonesia is today scheduled to complete the withdrawal of its 21,000 non-local soldiers from Aceh as part of a peace agreement to end a 29-year separatist insurgency in the tsunami-ravaged province.

An army spokesman, Lieutenant Colonel Eri Soetiko, said 3,353 soldiers will leave from the port of Lhokseumawe by the end of today. This will officially leave 14,700 troops in the province, compared with more than 35,000 before the signing of the August memorandum of understanding between the two sides.

Aceh bore the brunt of the Boxing Day 2004 earthquake and tsunami, with more than 169,000 people killed or missing and 600,000 losing their homes. The impact of the disaster played a significant role in bringing the warring sides together.

The Free Aceh Movement (Gam) rebels met their commitment to surrender 840 weapons earlier this month. On Tuesday, in an unexpected move, they announced they had disbanded Gam's armed wing. Analysts see this as the strongest sign yet that Gam is truly starting to trust Jakarta.

The Indonesian police are due to finish their pullout in the next few days, reducing their strength from 15,000 in August to 9,100.

International monitors from Europe and south-east Asia, who are overseeing the peace process, will start next week verifying that Indonesia does not have more than the limit stipulated in the agreement. "I don't think it's feasible to do it on the exact number," the chief monitor, Pieter Feith, told the Guardian yesterday. "Many units are under strength, for instance. But I don't think the [military] are playing games." Indonesian generals have repeatedly said they are committed to peace and the small number of violations of the agreement is seen as being testament to this.

Tension has increased in the past week, however, after Jakarta announced it wants to redeploy about 1,000 army engineers to Aceh to help with reconstruction in remote areas cut off to civilian contractors.

"This [deployment] is an unhealthy development, under whatever pretext," a Gam spokesman, Bachtiar Abdullah, told the Guardian. "This is undermining the memorandum of agreement because there should only be 14,700 troops in Aceh, period. But if the monitors are happy then we will have faith in them."

Mr Feith said that in order not to sour the rising confidence levels between the two sides, he told President Susilo Bambang Yudhoyono on Tuesday that any deployment "must be done in an inclusive way, in a transparent way and only after showing there's no demonstrable alternative to military engineers".

He said the engineers should also be unarmed and withdrawn before the monitors leave, a move scheduled for March 15. This is likely to be delayed, however, until the Indonesian parliament meets its commitment to the agreement by passing a law granting autonomy to Aceh.

The peace process is progressing much better than anyone expected after so many years of bitter conflict, which left at least 12,000 dead. But all analysts agree it has yet to become irreversible. "We're now going into the more political and ambiguous provisions of the agreement, so it will get a lot murkier," Mr Feith said.