Afghan police clashed with Taliban fighters outside the capital Kabul, leaving a dozen militants and an officer dead, while bombs blasts killed five more policemen, the government said.
The fresh violence was linked to a deadly insurgency led by the extremist Taliban, who are battling to wrest back power after being ousted from government by the 2001 US-led invasion.
The militants were killed on Monday in a sweep to clear Taliban from Musayi district about 15 kilometres (nine miles) south of Kabul, interior ministry spokesman Zemarai Bashary told AFP.
“The head of the district criminal investigation department was wounded and later died in hospital. Twelve enemies were also killed,” Bashary said.
Separately a rocket landed inside an international military base on the outskirts of Kabul and wounded three French soldiers preparing to head out in a convoy, a French military spokesman said.
One of the soldiers would be evacuated to France for treatment, Lieutenant Colonel Bertrand Fayet told AFP.
The French soldiers are among about 70,000 US-led and NATO-led troops deployed in Afghanistan to help the fragile nation fight extremism, which the West brands a direct threat.
In a suspected militant attack on the Afghan security forces, a roadside bomb blew up a police vehicle in the eastern province of Paktia and killed four policemen, the interior ministry said in a statement.
The vehicle was struck while taking part in an operation with the army and US-led troops in Zurmat district, it said.
A bomb ripped through another police vehicle on Tuesday in the eastern province of Nangarhar, killing a policeman and wounding two others, provincial government spokesman Ahmad Zia Ahmadzai said.
The Taliban-led insurgency has steadily gained strength in recent years, with 2008 the deadliest of the campaign.
British Prime Minister Gordon Brown visited Kabul on Monday to drum up support for a new strategy to tackle a “crucible of terrorism” on the Pakistan-Afghan border.