KABUL, Afghanistan >> The U.S. soldier who allegedly shot 16 Afghan villagers was caught on surveillance video that showed him walking up to his base and raising his arms in surrender, according to an Afghan official who viewed the footage.

The official said late Tuesday that U.S. authorities showed Afghan authorities the surveillance video to prove that only one perpetrator was involved in the Sunday shootings, which have sparked outrage across the country.

A delegation investigating the shootings was meeting in the southern city of Kandahar on Wednesday when a bomb hidden in a motorcycle exploded about 600 yards (meters) away. The blast killed one Afghan intelligence official and wounded three other people, but the delegation members were unharmed.

The day before, the delegation visited the two villages in Kandahar province where the shootings took place. Two villagers who lost relatives insisted that not one — but at least two — soldiers took part in the shootings. Afghan officials have also suggested that more than one shooter was involved.

The video, taken from an overhead blimp that films the area around the base, shows a soldier in a U.S. uniform approaching the south gate of the base with a traditional Afghan shawl hiding the weapon in his hand, the official said.

He then removes the shawl as he lays his weapon on the ground and raises his arms in surrender.

The official had not been shown any footage of the soldier leaving the base. The official spoke anonymously to discuss a private briefing.

Afghan lawmakers have demanded that the shooter, identified by U.S. officials as a staff sergeant, face a public trial inside Afghanistan. They have called on Afghan President Hamid Karzai to suspend any negotiations with the U.S. on a long-term military pact until this happens.

“No final decision has been made yet” on the location of the trial, said Col. Gary Kolb, a U.S. military spokesman in Afghanistan.

“We have done court martials in Afghanistan before, so we have the capability,” Kolb said. “They’ll take a look at all the circumstances and determine if they do it here or if it goes back to the States.”

The U.S. is holding the soldier, who military officials say slipped off a U.S. base before dawn Sunday, walked to the villages, barged into their homes and opened fire. Some of the corpses were burned. Eleven were from one family. Five other people were wounded.

The military said Tuesday there was probable cause to continue holding the soldier, who has not been named, in custody. U.S. Secretary of Defense Leon Panetta has said he could face capital punishment.

Panetta arrived in Afghanistan on Wednesday on a visit that was planned months before the weekend slaughter of Afghan villagers. But the trip propels Panetta into the center of escalating anti-American anger and sets the stage for some difficult discussions with Afghan leaders.

Panetta and other U.S. officials say the shooting spree should not derail the U.S. and NATO strategy of a gradual withdrawal of troops by the end of 2014. But it has further soured relations with war-weary Afghans, jeopardizing the U.S. strategy of working closely with Afghan forces so they can take over their country’s security.

Afghan Defense Minister Abdul Rahim Wardak called the massacre “deplorable” Wednesday but said the country must remember the bigger issues at stake, likely a reference to the fear that the Taliban could capitalize on a precipitous foreign withdrawal.

“I mean the stakes are much higher than this incident, which we have all have condemned, and I think we are assured that the U.S. authority will take appropriate action,” said Wardak in a press conference with German Defense Minister Thomas de Maiziere in Kabul.

President Barack Obama has pledged a thorough investigation, saying the U.S. was taking the case “as seriously as if it was our own citizens, and our children, who were murdered.”

The Taliban have vowed to take revenge for the shootings and on Tuesday fired on the government delegation visiting the villages that were attacked. One Afghan army soldier was killed and two other army personnel were wounded.

No group has yet claimed responsibility for the bombing Wednesday in Kandahar. The explosion occurred about 300 yards (meters) from the Afghan intelligence headquarters in the city, said the spokesman for the provincial governor, Zalmai Ayubi. One Afghan intelligence official was killed in the attack. Two of the three wounded were also intelligence officials, he said.

Elsewhere on southern Afghanistan, eight civilians were killed in Helmand province’s Marjah district when a roadside bomb struck their vehicle, said the provincial governor’s office.

Protesters in the east called for the death of the accused U.S. soldier Tuesday and burned an effigy of Obama as well as a cross, which they used as a symbol of people who — like many Americans — are Christians.

It was the first significant protest since the killings, which many had worried would spark another wave of deadly riots like those that followed the burning of Qurans at a U.S. base last month. Nearly a week of violent demonstrations and attacks left more than 30 dead, including six U.S. soldiers killed apparent reprisal attacks.

Military commanders have yet to release their final investigation on the Quran burnings, which U.S. officials say was a mistake. Five U.S. service members could face disciplinary action in connection with the incident.