BALANDI, Afghanistan >> Taliban militants opened fire Tuesday on a delegation of senior Afghan officials — including two of President Hamid Karzai’s brothers — visiting villages in southern Afghanistan where a U.S. soldier is suspected of killing 16 civilians.

The attack came as students in the east staged the first significant protest in response to Sunday’s shootings, raising worries of a repeat of the wave of violent demonstrations that rocked the nation after last month’s burning of Qurans by troops at a U.S. base.

The militants killed an Afghan soldier who was providing security for the delegation in Balandi village, said Gen. Abdul Razaq, the police chief for Kandahar province where the visit took place. Another Afghan soldier and a military prosecutor were wounded, he said.

The delegation was in a mosque for a memorial service for those killed Sunday when the gunfire erupted.

One of the president’s brothers, Qayum Karzai, said the attack didn’t seem serious to him.

“We were giving them our condolences, then we heard two very, very light shots,” said Karzai. “Then we assumed that it was the national army that started to fire in the air.”

He said the members of the delegation, which also included Kandahar Gov. Tooryalai Wesa and Minister of Border and Tribal Affairs Asadullah Khalid, were safe and headed back to Kandahar city.

Before the attack on the delegation, the Taliban vowed to kill and behead those responsible for the civilian deaths in the two villages in Panjwai district, considered the birthplace of the militant group.

Nine of the 16 killed were children, and three were women, according to President Karzai.

The U.S. has an Army staff sergeant in custody who is suspected of carrying out Sunday’s pre-dawn killings but has not released his name.

Villagers have described him stalking from house to house in the middle of the night, opening fire on sleeping families and then burning some of the dead bodies.

Their anger was evident Tuesday in discussions with the visiting officials before the attack cut the visit short.

“Today, the Kandahar governor was trying to explain to the villagers that he was only one soldier, that he was not a sane person and that he was sick,” said Abdul Rahim Ayubi, a Kandahar lawmaker who was part of the delegation.

“But the people were just shouting and they were very angry. They didn’t listen to the governor. They accused him of defending the Americans instead of defending the Kandahari people,” Ayubi said.

The delegation did manage before the shooting started to pay out compensation to family members of the victims — $2,000 for each death and $1,000 for each person wounded.

In the east, meanwhile, hundreds of students staged the first significant protest in response to the tragedy, shouting angry slogans against the U.S. and the American attacker.

The killings have caused outrage in Afghanistan but have not sparked the kind of violent protests seen last month after American soldiers burned Muslim holy books and other Islamic texts.

But the students protesting at a university in Jalalabad city, 80 miles (125 kilometers) east of the capital Kabul, were incensed.

“Death to America!” and “Death to the soldier who killed our civilians!” shouted the crowd.

Some carried a banner that called for a public trial of the soldier, who U.S. officials have identified as a married, 38-year-old father of two who was trained as a sniper and recently suffered a head injury in Iraq.

Other protesters burned an effigy of President Barack Obama.

“The reason we are protesting is because of the killing of innocent children and other civilians by this tyrant U.S. soldier,” said Sardar Wali, a university student. “We want the United Nations and the Afghan government to publicly try this guy.”

Taliban spokesman Zabiullah Mujahid said in a statement that the soldier should be tried as a war criminal and executed by the victims’ relatives.

Obama has expressed his shock and sadness and extended his condolences to the families of the victims. But he has also said the horrific episode would not speed up plans to pull out foreign forces, despite increasing opposition at home to the war in Afghanistan.

If the protests against the recent killings spread and become violent it could further complicate the issue, said Malcom Chalmers, a professor of security policy at Kings College in London.

“My instinct is that it (the killings) will not have much influence on the pace of withdrawal,” said Chalmers. “But if you see riots in Kandahar and Kabul and other cities, that could change.”

Photographs of dead toddlers wrapped in bloody blankets in Panjwai started to make the rounds in Afghanistan on Monday. The images were broadcast on Afghan TV stations, and people posted them on social network sites and blogs.

In the aftermath of the Quran burnings last month, over 30 people were killed in the protests and Afghan forces turned their guns on their supposed allies, killing six U.S. service members.

The Qurans and other Islamic books were taken from a detention facility and dumped in a burn pit because they were believed to contain extremist messages or inscriptions. A military official said at the time that it appeared detainees were exchanging messages by making notations in the texts.

U.S.-Afghan strains appeared to be easing as recently as Friday, when the two governments signed an agreement to gradually the transfer of Afghan detainees to Afghan control — a key step toward a pact to govern U.S. forces in the country after most combat troops leave in 2014.

But after the shooting, Afghan lawmakers called for a halt to negotiations on a bilateral pact with the U.S. until the soldier behind the shooting faces trial in Afghanistan.

“This is the saddest thing that has happened in Afghanistan in the past 10 years, to kill children and then put blankets on them and burn them,” said Abdul Khaliq Balakarzai, a parliamentarian from Kandahar. “We are calling on the Afghan president not to sign the strategic partnership before the trial of this man. We don’t need these foreign troops here. They just create problems.”

Previously, lawmakers had said they wanted the shooter tried in an Afghan court, but Balakarzai said Tuesday that they would be satisfied as long as the trial was held in Afghanistan and was public.

A group of parliamentarians had also been planning to visit the site, but it was not clear if that trip was still on following the attack on the delegation from Karzai.

The top U.S. commander in Afghanistan, Gen. John Allen, told CNN on Monday that the soldier did not leave his base undetected. An Afghan soldier saw him go and reported this to the Americans, who did a head count and realized that the suspect was missing. The Americans formed a search party, but Allen did not describe what happened after that.

Other U.S. officials have said initial reports indicate the soldier turned himself in after the shootings.

The soldier, who has been in the military for 11 years and served three tours in Iraq, was being held in pretrial confinement in Kandahar by the U.S. military while Army officials review his complete deployment and medical history, Pentagon officials said.

U.S. Secretary of Defense Leon Panetta said Monday that the soldier may face capital charges.

The soldier was deployed to Afghanistan on Dec. 3 with the 2nd Battalion, 3rd Infantry Regiment of the 3rd Stryker Brigade, 2nd Infantry Division, based at Joint Base Lewis-McChord located south of Seattle, according to a congressional source, speaking on the condition of anonymity because of the sensitivity of the matter.

He was sent on Feb. 1 to Belambai, the base located a half-mile (one kilometer) from one of the villages that was attacked, the source said.

A U.S. military spokesman in Kabul said he was responsible for providing base security.