WASHINGTON • The Pentagon scrambled Thursday to assure Afghans that it would aggressively investigate a video that shows U.S. Marines urinating on three corpses, while Afghans' reaction varied from outrage to resignation that the video merely reflected behavior that they think is typical of American troops.

Pentagon officials said the video appeared authentic and that they'd confirmed the identities of two of the four Marines shown in it.

In Afghanistan, while no major protests were reported the day after the video surfaced online — purporting to show four Marines standing in a semicircle and urinating on dead Afghans — one resident said he wasn't surprised.

"I know a lot of horrible things happen in the south and nobody but the locals know about it," said Jamal Karimi, 32, referring to southern Afghanistan, where American forces have maintained a large troop presence.

"Such things happen all the time, and people talk about it but media hardly report them," said Karimi, a shopkeeper from the southern city of Kandahar.

In Washington, Secretary of Defense Leon Panetta called Afghan President Hamid Karzai about the video, calling it "utterly deplorable." The commandant of the Marine Corps and the secretary of the Navy used similar language to express disgust over what would be the latest example of U.S. troops treating those killed or captured on the battlefield as trophies.

Karzai said: "This act by American soldiers is completely inhumane and condemnable in the strongest possible terms. We expressly ask the U.S. government to urgently investigate the video and apply the most severe punishment to anyone found guilty in this crime."

Pentagon officials said the incident was being investigated, but they confirmed that the troops were members of Team 4, 3rd Battalion, 2nd Marines, out of Camp Lejeune, N.C., which was deployed in southern Afghanistan's Helmand province from last March to August. The Marines' identities weren't immediately revealed.

White House press secretary Jay Carney said the behavior the video apparently depicted was "deplorable, reprehensible and unacceptable." He said he didn't know whether President Barack Obama had seen the video, but that "he is certainly aware of it and shares in the sentiment expressed by Secretary Panetta."

The Taliban released a statement of condemnation but said they wouldn't impede U.S. efforts to begin peace talks with them because the video showed just a 'small percentage of the invaders' atrocities."

In the United States, advocacy groups said Afghans' muted initial reaction was likely because they'd not only come to think that American troops commonly behaved this way, but also were largely skeptical about the United States' commitment to punishing such abuses. The words of high-level officials have little impact because, residents say, they've watched as egregious incidents over the last decade of war often have resulted in charges dropped against offending U.S. troops and commanders, or never filed.

"The lack of accountability suggests a culture of impunity, particularly the failure to charge high-level commanders and officials, both civilian and military," said Andrea Prasow, a senior counterterrorism counselor at Human Rights Watch.