MANILA, Philippines — A predominantly Muslim region in the southern Philippines held its first parliamentary elections on Monday, seen as a crucial step in the long quest for self-rule after decades of insurgency and violence.

The Bangsamoro Autonomous Region in Muslim Mindanao was established under a 2014 peace deal in which the largest Muslim rebel group gave up its goal of a separate Muslim state in the south of the largely Roman Catholic country in exchange for broader autonomy. The group’s 40,000 fighters promised to demobilize and join civilian life.

Officials said the elections were largely peaceful despite a person being killed following commotion in a polling station in the main city of Cotabato on Monday. Some supporters of a political party also trashed two vehicles belonging to a rival politician using steel bars.

Three people were killed late Sunday and 15 wounded in a shooting in Cotabato, which houses the Bangsamoro government offices, including parliament.

Meanwhile, the town of Maluso on Basilan Island was put under the control of the Commission on Elections after pre-shaded ballots were found in 36 out of 68 precincts. Commission’s Chairman Erwin Garcia said he immediately ordered the reprinting of ballots and that voting will be delayed there. He said those responsible will be held accountable.

As of early Monday, 98.1% of the region’s polling stations were open to voters, according to the commission.

“Whoever wins, hopefully we will see change,” said Sittie Ashuya L. H. Omar, a 22-year-old voter from the city of Marawi. “Hopefully they can implement their promises”

Eighty seats are at stake in the elections that will determine members of parliament. The region comprises five provinces, three cities and 63 villages with nearly 2.4 million voters. Election officials said they expected an 80% turnout after polling was postponed for several years.

The region’s chief minister, who heads the executive branch, will be elected by parliament in its first session.

“The elections stand on generations of Bangsamoro struggle for homeland, identity, and self-determination, in the face of dispossession, marginalization, conflict and sacrifice,” Garcia said in an earlier statement

In May 2017, Islamic State group-linked militants laid siege on Marawi, triggering five months of ground assaults and airstrikes that left more than 1,100 people, mostly militants, dead and destroyed the mosque-studded city’s commercial and residential districts.

Since the 1970s, about 150,000 combatants and civilians have died in the southern Philippines, while development was stunted in the country’s poorest region. Western and Asian governments feared the tenacious insurgencies could help foster Islamic extremism in Southeast Asia. With bombing attacks and kidnappings, Mindanao used to be a haven for al-Qaida and the IS before a U.S.-backed Philippine offensive weakened the militants.

More than 20,000 soldiers and police forces were deployed for elections, while troops carrying long arms patrolled roadsides.

Monday’s vote ended at 7 p.m. local time, except in areas where voting was delayed, extending the closing time.

Candidates running unopposed are expected to be declared winners late Monday.