An explosion followed by gunfire hit the center of the Afghan capital Kabul on Saturday, close to the communications ministry and one of the city's main hotels, officials said.
The blast followed several months of relative calm in Kabul, which coincided with talks between U.S. and Taliban officials aimed at opening the way for formal peace negotiations to end more than 17 years of war in Afghanistan.
There was no immediate claim of responsibility or information on casualties.
"The information that we have is four attackers have placed themselves near the communication ministry and are engaged in gun battles with the Afghan security forces," Amanduddin Shariati, a security official in Kabul told AFP.
Interior ministry spokesman Nasrat Rahimi said an explosion was heard near the communication ministry around 11:40 am (0710 GMT), followed by sporadic gunfire.
Local television footage showed a small plume of smoke near the ministry, and people climbing out the windows on a lower level.
Intermittent firing could still be heard more one hour after the blast, and the area had been cordoned off by security forces.
The communication ministry is located in downtown Kabul, about two kilometers (1.25 miles) from the green zone.
The explosion was also close to the heavily fortified Serena Hotel, one of the very few hotels still used by foreign visitors, in one of the main commercial areas of the city.
While heavy fighting has carried on across Afghanistan and Taliban militants have announced their now customary spring offensive, there have been no large scale attacks on civilian targets in Kabul in recent weeks.
The Afghan branch of the Daesh terror group has also previously carried out multiple deadly attacks in Kabul.
