A suicide bomber on Thursday killed two Afghan policemen and injured four others in the north of the country, including a senior commander, police said, dpa reported.
Samiullah Qatra, Kunduz's police chief said that Abdullah Gard, the commander of the police's special forces in Kunduz, was injured and two of his bodyguards were killed in the northern province.
The unit carries out night raids against suspected Taliban militants.
In a separate incident, residents in the southern province of Helmand cut off the ears of a man accused of planting a roadside bomb that killed two children.
The two children were killed when the car in which they were travelling hit a landmine in the Safar area of Garamsir district in Helmand, the provincial governor's office said in a statement.
Community residents moved to avenge the children's death by attacking a man believed to have planted the landmine.
"The people were outraged and they planned to hang him in public. But the police stopped it. They had already cut his ears off by the time they got there," Daud Ahmadi, the spokesman for the provincial governor said.
Six others passengers were injured, the statement said. They were travelling to attend a wedding party.
The governor's office condemned the attack, calling it an "evil and anti-Islamic act by the terrorists."
The attack comes just two days after three suicide bombers targeted a police office in neighbouring Musa Qala district. Eight policemen died in that incident.
Helmand has remained volatile, with one of the highest civilian and military casualty rates, despite claims by Western military officials of fragile peace gains.