No militant group immediately claimed responsibility for the three attacks, which come amid an upsurge in violence in Afghanistan as clashes intensify between government forces and Taliban insurgents.
A string of near-daily roadside bombings in recent weeks has killed government officials, judges, journalists and activists.
The bloodshed comes as US-brokered peace talks in Qatar between the Taliban and representatives of the Afghan government have staggered in recent months.
President Joe Biden's team is reviewing a peace-building deal that the government of his predecessor Donald Trump sealed with the Taliban in February 2020. The pact requires all American and allied forces to leave the country by May 1st.
The United States has reduced the number of troops in Afghanistan to 2,500 from the 12,000 there when the agreement was signed. But violence remains high, with the US and Afghan governments largely blaming the Taliban.
On Saturday, a police spokesman in southern Kandahar province said a blast there was caused by a Humvee packed with explosives that targeted a police outpost, injuring seven police personnel.
Afghanistan's Defense Ministry said "18 Taliban terrorists were killed and 9 others were wounded" in an operation in Arghandab district of Kandahar province on Friday night.
An explosion targeted the police commander in the Chapa Dara district of eastern Kunar province, killing four local police personnel, including the commander, said a provincial police spokesman.A roadside bomb blast injured three civilians in Jalalabad, the capital of eastern Nangarhar province.