Last Updated 12:18 a.m. ET
(CBS/AP) KABUL, Afghanistan - A U.S. service member came out of his base in southern Afghanistan on Sunday and started shooting Afghan civilians, killing 16, including woman and children, Afghan officials said.
The shooting spree occurred in Panjwai district of Kandahar province. Little is known about the shooter, although CBS News has learned he was an U.S. Army sergeant in a Stryker Brigade based at Fort Lewis, in Washington state.
Afghan President Hamid Karzai said 16 people were killed, including nine children and three women.
"This is an assassination, an intentional killing of innocent civilians and cannot be forgiven," Karzai said in a statement. He said he has repeatedly demanded the U.S. stop killing Afghan civilians.
Five people were wounded in the pre-dawn attack, including a 15-year-old boy named Rafiullah who was shot in the leg and spoke to the president over the telephone. He described how the American soldier entered his house in the middle of the night, woke up his family and began shooting them, according to Karzai's statement.
President Barack Obama called the shootings "tragic and shocking," and said he was deeply saddened by the reported killing and wounding of Afghan civilians.
In a statement Mr. Obama said, "I offer my condolences to the families and loved ones of those who lost their lives, and to the people of Afghanistan, who have endured too much violence and suffering." He also asserted the incident "does not represent the exceptional character of our military and the respect that the United States has for the people of Afghanistan."
The attack took place in two villages in the Panjwai district of southern Kandahar province. The villages -- Balandi and Alkozai -- are about 500 yards away from a U.S. base. The shooting started around 3 a.m., said Asadullah Khalid, the government representative for southern Afghanistan and a member of the delegation that went to investigate the incident.
A resident of the village of Alkozai, Abdul Baqi, told the AP that, based on accounts of his neighbors, the American gunman went into three different houses and opened fire.
"When it was happening in the middle of the night, we were inside our houses. I heard gunshots and then silence and then gunshots again," Baqi said.
Speaking from Kabul, CBS News correspondent Mandy Clark reports that, according to an Afghan official, 11 civilians including women and children were killed in one home.The suspect - a sergeant, married with two children, who had served three tours in Iraq and began his first deployment to Afghanistan in December, according to a senior U.S. official - was being held by the U.S. miltary and an investigation was ongoing.
Clark said there is no indication of a motivation in the attack. "They haven't made any links to the victims and the soldiers, so it's very unclear why he went on this shooting rampage," said Clark.
An AP photographer saw the bodies - some of them burned and some covered with blankets - in the villages of Alkozai and Balandi in Kandahar province's Panjwai district. The villages are about 500 yards away from a U.S. base.
Villagers packed inside a minibus looked on with concern as a woman spoke to reporters. She pulled back a blanket to reveal the body of a smaller child wearing what appeared to be red pajamas. A third dead child lay amid a pile of green blankets in the bed of a truck.
Gen. John R. Allen, Commander of the International Security Assistance Force (ISAF), said in a statement, "I was shocked and saddened to hear of the shooting incident today in Kandahar Province. I offer my profound regret and deepest condolences to the victims and their families. I pledge to all the noble people of Afghanistan my commitment to a rapid and thorough investigation.
"In the meantime, we will continue to offer medical care for those who were injured in this shooting," Gen. Allen said. "We will maintain custody of the U.S. service member alleged to have perpetrated this attack. And we will cooperate fully with local Afghan authorities as we ascertain all the facts."
He said the "deeply appalling incident" in no way represents the values of ISAF and coalition troops, said he was absolutely dedicated to making sure anyone found to have committed wrong-doing is held fully accountable.
Gen. Carsten Jacobson, a spokesperson for the ISAF, speaking in a video posted to Natochannel and on YouTube, also expressed "deep regrets" and "sorrow" for the members of the families of those who perished.
He did not did not link this shooting to other recent incidents, such the burning of Qurans and the subsequent protests which led to the deaths of six U.S. service members and more than two dozen Afghan civilians. ,/P>
"Of course it is a very tragic event, it looks like the act of an individual, but we have to find out what the background behind it is . . . look into the case in detail."
Twelve of the dead were from Balandi, said Samad Khan, a farmer who lost all 11 members of his family, including women and children. Khan was away from the village when the incident occurred and returned to find his family members shot and burned. One of his neighbors was also killed, he said.
"This is an anti-human and anti-Islamic act," said Khan. "Nobody is allowed in any religion in the world to kill children and women."
Khan demanded that Afghan President Hamid Karzai punish the American shooter.
"Otherwise we will make a decision," said Khan. "He should be handed over to us."
Residents in Alkozai village also demanded that Karzai punish the American or hand him over to the villagers. The four people killed in the village were all from one family, said a female relative who was shouting in anger. She did not give her name because of the conservative nature of local society.
"No Taliban were here. No gun battle was going on," said the woman. "We don't know why this foreign soldier came and killed our innocent family members. Either he was drunk or he was enjoying killing civilians."
The Taliban called the shootings the latest sign that international forces are working against the Afghan people.
"The so-called American peace keepers have once again quenched their thirst with the blood of innocent Afghan civilians in Kandahar province," The Taliban said in a statement posted on a website used by the insurgent group.
Appearing on "Face the Nation," CBS News national security correspondent David Martin said that motive may be besides the point: "The number one mission for U.S. troops in Afghanistan is to protect Afghan civilians. For an American soldier just to open fire on Afghan civilians just undercuts the mission of the U.S. troops in Afghanistan."
Sediq Sediqqi of the Afghan Interior Ministry condemned the attack, telling Reuters, "We condemn the shootings in the strongest terms possible and this will be fully investigated."This attack could not have come at a worse time, said CBS News correspondent Mandy Clark. Last month, Afghans held mass protests against American troops after U.S. soldiers mistakenly burned copies of the Quran. Six American soldiers were killed in retaliation attacks.
The worry now is how the Afghan public will react to this attack.
Also appearing on "Face the Nation" this morning, Republican presidential candidate Newt Gingrich said it was time for the U.S. to leave Afghanistan, adding that the U.S. is not "ruthless enough" to affect fundamental change.
"I think we have to reassess the entire region," he told Bob Schieffer. "I think we need to reconsider the whole mission. We need to understand that our being the middle of countries like Afghanistan is counter-productive. We are not in a position to force them to change."
U.S. forces are investigating the shooting in cooperation with Afghan authorities, NATO spokesman Justin Brockhoff said. He said it was not clear if the alleged shooter knew the victims.
There were reports of protests following the shooting.
The shooting comes after weeks of tense relations between U.S. forces and their Afghan hosts following the burning of Qurans and other religious materials at an American base. Though U.S. officials apologized and said the burning was an accident, the incident sparked violent protests and attacks that killed some 30 people.
Meanwhile, a prominent Afghan women's rights activist said gunmen attacked her office in a western province overnight in an apparent assassination attempt.
Malalai Joya, a former Afghan lawmaker and vocal critic of both the Taliban and of criminality in the Afghan government, said the attack on her office in Farah province was the sixth attempt on her life to date.
Armed men tried to storm the compound late in the night on Saturday, she said. The attackers did not get into the building but two of her guards were seriously injured and are currently in the hospital.
Joya said she was in Kabul at the time but had planned a trip to Farah soon and news of that may have leaked out. She said she believes the attackers thought she was in the building.