A loud explosion and follow-up gunfire were heard near the Afghan communication ministry in central Kabul on Saturday, officials said.
The blast occurred a day after talks collapsed between the Taliban and Afghan representatives, but no one claimed immediate responsibility and there was no immediate word on casualties.
Interior ministry spokesman Nasrat Rahimi said an explosion was heard near the communication ministry around 11:40 am (0710 GMT), followed by sporadic gunfire.
Intermittent firing could still be heard more than 30 minutes after the blast, and the area had been cordoned off by security forces.
The communication ministry is located in downtown Kabul, about two kilometres (1.25 miles) from the green zone.
The explosion comes the week after the Taliban announced their annual spring offensive and amid ongoing fighting across Afghanistan.
The Afghan branch of the Islamic State group has also previously carried out multiple deadly attacks in Kabul.