Kabul - Four suspected al-Qaeda-associated militants and 12 Taliban insurgents were killed while 20 others were wounded in two separate operations in Afghanistan while three Afghan police injured in a suicide attack in Khost province, officials said on Friday.

Arsala Jamal, Khost province governor, said that at least three Afghan police were injured in a suicide attack in Bak district of south-eastern Khost province.

A suicide attacker detonated an explosives-filled car near a police vehicle just outside of Khost city, injuring three police official, the governor said.

According to the officials, there were no civilian casualties reported.

Meanwhile, the US-led coalition in Afghanistan said in a statement that its troops killed the four suspected al-Qaeda-associated militants during an operation in Zurmat district of the eastern province of Paktia on Thursday.

"Coalition forces targeted an al-Qaeda-associated militant known to assist local Taliban leaders with the movement of Arabs and other foreign fighters into Afghanistan," it added.

But the statement did not identify the militants' nationalities.

"These fighters have carried out numerous suicide and improvised explosive device (IED) attacks in the region," the US military statement said.

A search of the area revealed the militants were heavily armed with multiple AK-47s assault rifles, rocket-propelled grenades, hand grenades and pistols. These items were destroyed to prevent future use, it said.

Meanwhile, officials in Maidan Wardak province said that at least 12 Taliban militants were killed and 20 others wounded during an operation Thursday night.

The militants were killed in a US-led coalition airstrike in the Haft Asyab area of the Saeed Abdad district, Adam Khan Sirat, spokesman for the Maidan Wardak governor, told Deutsche Presse-Agentur dpa.

A local Taliban commander by the name of Mullah Asif was among the wounded militants, said Sirat, adding, "Fortunately there were no civilian casualties in this incident."

A Taliban spokesman confirmed the incident but said only three of their supporters were killed.

Zabihullah Mujahid, a spokesman of the Taliban insurgents, also claimed that on Thursday night their militants targeted a foreign forces military convoy in the Haft Asyab area of Saeed Abdad district and killed some foreign troops.

He did not provide more detail about the international troops' casualties.

US forces so far have not commented on the clash. (dpa)