A demonstration in downtown Kabul turned violent Friday as police fired at rock-throwing protesters demanding better security in the Afghan capital in the wake of a powerful truck bomb attack that killed 90 people. At least four demonstrators were killed and police injured, authorities said.

More than 1,000 people demonstrated as Afghans mourned the victims of a massive truck bomb that also wounded more than 450 on Wednesday. It was one of the worst extremist attacks since the drawdown of foreign forces in 2014 and raised fears about the government's ability to protect its citizens nearly 16 years into a war with insurgents.

Police fired their weapons — into the air as a warning at first— as about a hundred of the demonstrators rushed toward them, some throwing rocks. As the protesters attempted to move closer to the Presidential Palace, police sprayed them with hoses from a water tanker and later fired tear gas.

Demonstrators calling for President Ashraf Ghani to step down and chanting "Death to the Taliban" clashed with police near the bombing site, prompting officials to respond with live rounds, tear gas and water cannon as some protesters tried to overrun a security cordon.

The bombing during the holy month of Ramadan highlighted the ability of militants to strike even in the capital's most secure district, home to the presidential palace and foreign embassies that are enveloped in a maze of concrete blast walls. Angry citizens have demanded answers from the government over the perceived intelligence failure leading to the assault, which underscores spiraling insecurity in Afghanistan.

"Our brothers and sisters were martyred in the bloody attack on Wednesday, and our leaders are doing nothing to stop this carnage," Rahila Jafari, a civil society activist, said during the protest. "We want justice, we want the perpetrators of the attack to be hanged to death."

Most of the casualties from the truck bombing were civilians, including women and children, officials have said.