A powerful blast echoed around the Afghan capital as a suicide car bomber hit a NATO military convoy on the main road to the airport, around 500 metres (550 yards) from the US embassy, killing at least one Afghan civilian and wounding around 20.
Hours earlier at least two civilians were killed when a suicide truck bomb detonated at the gate of the police headquarters in Lashkar Gah, the capital of volatile Helmand province.
Today's violence came less than two days after 11 soldiers were killed in a Taliban ambush in the normally relatively peaceful western province of Herat.
"It was a suicide car bomber targeting a convoy of foreign forces in Kabul," interior ministry spokesman Sediq Sediqqi said.
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"In the aftermath of today's terrorist attack in Kabul, one was killed and 22 more injured, all civilians," he said.
A spokeswoman for the NATO mission in Afghanistan, Captain Susan Harrington, confirmed a convoy had been attacked and said two coalition personnel had been wounded.
In Helmand, provincial police spokesman Farid Ahmad Obaid told AFP the police headquarters attack left at least two civilians dead and 40 wounded.
Provincial police chief Nabi Jan Mullahkhil told reporters three attackers were involved.
"Two attackers were killed in the explosion while the third one was injured and as he tried to escape the police shot him," he said.
Provincial spokesman Omar Zhwak said most of the wounded were hit inside their homes by flying glass.
A doctor at the emergency hospital in Lashkar Gah said 40 civilians were brought to the hospital.
After the Helmand attack a small blast hit a military vehicle in Kabul, police said, though there were no casualties.