A search was under way Friday for two NATO soldiers who failed to return from a routine supply mission in western Afghanistan, officials said.

"We continue exhaustive search and rescue operations to locate our missing service members," a spokeswoman for the international forces, Capt. Jane Campbell of the U.S. Navy, said. "We are doing everything we can to find them."

They have been missing since Wednesday. When soldiers are missing, the fear is that they have been either been captured or killed, The New York Times said.

Meanwhile, Taliban spokesman Qari Yousuf Ahmadi said the bodies of two American soldiers allegedly drowned during a gun battle were found in Badghis province Wednesday, the Los Angeles Times reported.

NATO also reported two more Americans died Thursday, from roadside bombs in southern Afghanistan.