The rebel group broke off from the Moro Islamic Liberation Front, the largest Muslim rebel group in the south, after it entered into peace talks and later signed a Muslim autonomy deal with the government in 2014.
Baldomar said government forces locked down the town centre, where the public market is located, and closed a highway at the height of the hourslong rebel occupation of the market.
Datu Paglas Vice Mayor Mohammad Paglas, however, gave a different account and told reporters that the mostly young Muslim rebels arrived on board five trucks in the town centre Friday to rest and mark the holy fasting month of Ramadan.
Baldomar said some of the gunmen opened fire on civilian motorists, who were trapped along the highway.
They took over buildings, including banks, school campuses and a hospital, before troops quelled the insurrection after five months with the help of surveillance aircraft deployed by the U.S.