The Kabul-Kandahar Highway, a main route which connects the capital city with southern provinces, was closed to traffic following Taliban attack on government forces.
The attack happened in areas related to Maidan Wardak province, sources said.
The clashes are ongoing and dozens of vehicles have stopped on the two sides of the highway, eyewitnesses said.
Maidan Wardak officials said government forces have started their operation to reopen the highway.
Taliban confirmed the clash in a statement.
Officials have not provided details on possible causalities in the clashes.