DAMASCUS—Syrian rebel leader Ahmed al-Sharaa declared himself president, canceled the constitution and disbanded the national army and all opposition parties and armed groups, including his own, in a step toward transitioning away from the era of Bashar al-Assad.

The Syrian rebel group that ousted Bashar al-Assad last month dissolved parliament, dismantled the country’s armed apparatus and appointed its de facto leader the country’s new president, a series of moves meant to clear the way for a political transition,

Syria’s de facto leader Ahmad al-Sharaa was on Wednesday declared president by a group of top military commanders.