KABUL, Afghanistan (AP) — A military raid on a clinic in Afghanistan that led to the deaths of three people almost certainly involved international troops, a Swedish non-government organization that runs the clinic said on Wednesday.

Jorgen Holmstrom, country director of the Swedish Committee for Afghanistan, said Wednesday that two patients in its clinic in Wardak province and a boy were taken away and killed on the night of Feb. 17.

Earlier indications that foreign troops were involved had been confirmed by the U.N.'s assistance mission in Afghanistan, he said in a statement.

"Through information we received through the United Nations Assistance Mission in Afghanistan and information from our own staff, we believe it is almost certainly clear that international troops took part in the raid conducted against the clinic," the SCA said in a statement.

It said clinic staff believed that at least two people involved in the raid "spoke a language that sounded like English." It added that one person at the clinic said they wore "foreign uniforms."

Earlier, the SCA's communications coordinator Bjorn Lindh said the three were taken to a nearby bazaar and killed.

The SCA's Wednesday statement demanded the Afghan government and foreign forces provide a detailed explanation of the incident. "An independent investigation of the incident must be implemented," Holmstrom said.

UNAMA said in a statement this week that Interior Ministry special forces and international forces had conducted the operation.

The spokesman for the U.S.-NATO mission in Afghanistan, Army Col. Mike Lawhorn, says an investigation into the incident has begun.

The SCA incident follows the American military bombing of a hospital in the northern city of Kunduz by a U.S. AC-130 gunship on Oct. 3 which killed 42 people. The outgoing commander of U.S.-NATO forces in Afghanistan, Gen. John F. Campbell, said that attack was a mistake.