KABUL — An anti-government protest spiraled into a deadly street battle Friday, with security forces opening fire and using armored vehicles to chase demonstrators angered by a massive truck bombing earlier this week.

At least two demonstrators were killed, according to police, one of whom was reported to be the son of a senior legislator. There were unconfirmed reports of up to eight people dead and 10 wounded in the melee, which lasted for several hours and shut down central Kabul.

Before noon, thousands of people converged on the site of Wednesday’s blast in Kabul’s diplomatic zone, shouting chants against President Ashraf Ghani and hoisting banners with gruesome photographs from the bombing. The attack left more than 100 people dead and 450 injured.

The march — which included professionals, students and civic activists — remained largely peaceful until one group of protesters tried to reach the gates of Ghani’s palace three blocks away.

Security forces opened fire with mostly warning shots in the air, but protesters and others later claimed that gunfire caused casualties. One body was taken to a hospital, leaving a large pool of blood.