Banda Aceh – Political parties in Indonesia's Aceh province pledged peace Friday for the first national elections since government and rebel forces signed a deal to end decades of war.

Their declaration came shortly after a report by the International Crisis Group (ICG) said Aceh is tense ahead of the elections, and the current peace should not be taken for granted.

Leaders of all but four of the 44 parties that will contest the national and provincial elections in Aceh next April read out their pledge in front of the grand mosque in Banda Aceh, the provincial capital.

As part of efforts to secure what the declaration called "enduring peace" in the province, party leaders vowed to abide by electoral rules and not to engage in intimidation, provocation or violence.

Rebels from the Free Aceh Movement (GAM) signed a peace pact with the Indonesian government in Helsinki in 2005, giving up their fight for independence in return for broad-ranging autonomy. The deal ended almost three decades of violence that claimed more than 15,000 lives.

A gubernatorial election in 2006 proceeded with relatively little trouble and a former rebel leader was named the winner.

GAM members have formed the Aceh Party (Partai Aceh), chaired by the former guerrilla commander Muzakkir Manaf, which ICG said is the party to beat in next year's vote.

But Partai Aceh did not join in Friday's ceremony. It was not immediately clear why. "We regret there is a party that did not attend," said Aceh deputy governor Muhammad Nazar, a key figure in Partai SIRA.

The provincial police chief, Inspector General Rismawan, told reporters that his officers will conduct special operations to help ensure a calm campaign. "I'm certain the election in Aceh will be peaceful," he said.

Violence has been rare under the peace, but state media reported a grenade blast damaged Manaf's home this week. Police said two people were shot dead during a gun battle between police and suspected criminals on Tuesday.