US ambassador: Taliban could 'regenerate' if troops withdraw from Afghanistan now

As shocking details continue to emerge from the shooting deaths in Afghanistan last weekend said to have been carried out by a rouge U.S. soldier, the top American diplomat in the region said he understands public fatigue with the war after more than a decade, but also stressed the need to stay the course.

"I understand that people are tired," U.S. Ambassador to Afghanistan Ryan Crocker told Fox News in an exclusive interview Monday.

"I'm tired too," he said. "I've been deployed to Afghanistan, Pakistan and Iraq going on seven years now since 9/11. So, believe me, I understand what feeling tired means."

A new Washington Post/ABC poll shows 60 percent of Americans surveyed think the Afghan war is not worth it, while 54 percent want U.S. troops to come home.

Speaking on Fox News Sunday, U.S. presidential hopeful Newt Gingrich was sympathetic to Americans with that view. "I think it's very likely that we have lost, tragically lost the lives and suffered injuries to a considerable number of young Americans on a mission that we're going to discover is not doable," Gingrich said.

But Ambassador Crocker says leaving now would be disastrous.

"These are the stakes if we decide that we are tired of it, don't want to do it anymore," Crocker said. "Well, the Taliban isn't that tired and Al Qaeda, badly damaged, would be able to regenerate if the Taliban took the country over again."

Crocker called that scenario another “pre-9/11 situation."

Meanwhile, Fox News has learned that the alleged shooter, who officials say will be charged in a military court with murdering at least 16 Afghan civilians, suffered from a traumatic brain injury during one his three previous deployments in Iraq.

Officials also say the alleged shooter was suffering from "family issues," possibly with his wife.

His youngest victim was just two years old. Eyewitnesses said the shooter burned the bodies before he left, evidence of which can be viewed in video footage from the scene.

The Army is withholding the identity of the staff sergeant, an Army sniper who has two children of his own and is based out of Joint Base Lewis-McChord in Washington state.

President Obama in an interview Monday said he is still determined to bring troops home as planned.