Story highlights 2 were U.S. military personnel, and the third was Polish, a source says

ISAF says 3 of its members were killed

13 Afghan civilians are among the wounded

U.S. Embassy sounds "duck-and-cover" alarm as sky fills with smoke

Three members of NATO's International Security Assistance Force were killed in an attack in Kabul on Tuesday, the coalition said.

Two were U.S. military personnel, and the third was Polish, a U.S. defense official said.

The Taliban claimed responsibility for a suicide car bombing targeting a convoy of foreign forces in the Afghan capital, the militant group's spokesman Zabiullah Mujahid said.

A large plume of smoke filled the sky over Kabul, and the U.S. Embassy sounded its "duck-and-cover" alarm.

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Witness Sakhi Ahmad said the explosion took place on Kabul International Airport Road, near the Supreme Court compound.

ISAF and Afghan officials are investigating the blast, the coalition said. It did not identify the names or nationalities of those killed.

At least 13 Afghan civilians were also wounded in the attack, Afghan Interior Ministry spokesman Sediq Sediqqi said. He said 17 civilian vehicles were damaged in the blast.

The explosion in Kabul came a day after a man wearing an Afghan National Army uniform turned his weapon against ISAF members in western Afghanistan on Monday, the coalition said.

"ISAF continues to train, advise and assist the ANSF (Afghan National Security Forces), and does not view these incidents as representative of the positive relationship between our forces," ISAF said.

Most NATO troops are due to withdraw from Afghanistan by the end of this year as the U.S.-led war effort against the Taliban winds down.

The latest violence comes as Afghanistan grapples with the messy fallout from its presidential election this year.