(CNN) -- Security was tightened in and around Kabul on Sunday with 7,000 additional police officers deployed ahead of Monday's 89th observance of Afghanistan's independence from Great Britain.
An Afghan policeman stops a vehicle at a checkpoint in Kabul, where security has been tightened.
Police were seen at newly established security checkpoints looking at every passing vehicle Sunday. Increased foot patrols were also apparent.
An Interior Ministry official said it was the biggest police operation in Kabul in several months.
Also on Sunday, dozens of Taliban militants were killed after they ambushed a convoy carrying supplies for NATO forces in southern Afghanistan, an Afghan official said.
Five security forces who worked for a private company were killed in the attack, in Zabul province, said Gulab Shah Alikhail, the deputy governor.
After the ambush, Afghan army forces were called in, Alikhail said.
Alikhail put the militants' death toll at 32.
On Saturday, a roadside bomb killed 10 Afghan police officers in Kandahar province, according to Police Chief Matiullah Khan.
Khan blamed the Taliban and their al Qaeda associates for the attack.
"Who else is conducting this kind of cowardly acts except for the Taliban and al Qaeda people," he said.
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