KABUL: Two NATO soldiers are missing in western Afghanistan after a routine resupply mission, the alliance said Friday, but officials indicated it was unlikely they had been taken captive.

Local police said the two were Americans who were swept away by a river in the western province of Badghis.

The two went missing on Wednesday, NATO forces headquarters in Afghanistan said in a statement. It did not specify their nationality or which province they had been in, or provide any details of the resupply mission.

Military officials, who spoke on condition of anonymity due to command policy, indicated that they did not suspect the case was similar to that of an American soldier who was captured by insurgents in eastern Afghanistan on June 30.

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"We continue exhaustive search and rescue operations to locate our missing service members," spokeswoman Navy Capt. Jane Campbell said in the NATO statement. "We are doing everything we can to find them."

The statement said the two service members' families have been notified, and that no further information would be released while the rescue operation continued and the incident was being investigated.

Western regional police Chief Gen. Ikram Uddin Yawar said two American soldiers were swept away by a river while trying to save two boxes that had fallen into the water while being airdropped during a resupply mission in the Bala Murghab district of Badghis province.

The deputy police chief of Badghis province, Abdul Jabar, said a helicopter had airdropped food parcels at a coalition base, but that strong winds had blown one box into the river and that two soldiers had been swept away by strong currents while trying to recoup the parcel. He said Afghan police had been helping coalition forces in the search Thursday and Friday but had been unable to find the two soldiers.

NATO forces operating in western Afghanistan are mainly from the United States, Italy, Spain and Lithuania. The Defense Ministry in Vilnius said no Lithuanians were reported missing, while the Apcom news agency in Rome cited unidentified Italian defense officials as saying the two were not Italians.

The soldier who disappeared on June 30 near Afghanistan's border with Pakistan has still not been found. He was shown as a Taliban captive in a propaganda video in July.US military officials have said little about the search for 23-year-old Pfc. Bowe R. Bergdahl for safety reasons, and it is unclear whether he is being held in Afghanistan or Pakistan.

Separately Friday, NATO said two American service members were killed Thursday by a roadside bomb in southern Afghanistan. The statement gave no further details.

The deaths bring to three the number ofUS service members killed in the Afghan war so far this month. October was the deadliest month of the eight-year war forUS forces with 59 deaths reported.