KABUL, Afghanistan -- At least three civilians were killed by gunmen inside a mosque in eastern Afghanistan on Friday, the Interior Ministry said.

The ministry said that nine others were wounded in the Friday night attack in Gardez, the capital of Paktia province, in a statement released Saturday.

The ministry strongly condemned the attack and called it "an act against Islam and humanity." It said the civilians were attacked while praying.

There was no immediate claim of responsibility for the attack, but the Taliban and Haqqani network are active in Paktia and neighboring provinces and often target government officials as well as Afghan security forces in the region.

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In a separate report from southern Helmand province, at least two border police officers were killed Friday night after their checkpoint was struck by U.S. military forces during a joint operation, said Omar Zwak, spokesman for the provincial governor in Helmand.

Zwak said that three other policemen were wounded in the airstrike carried out during the operation against insurgents in the Nad Ali district.

"What we have so far is the initial report of the air strike" said Zwak, adding that an investigation was underway and that the dead toll could rise.

There was no immediate comment from the U.S. military on the airstrike in Helmand province.