GENEVA (Reuters) - If investigators identify who was to blame for the deadly Sept. 19 attack on a U.N. aid convoy in Syria, the “war crime” could be brought to the Security Council, U.N. Deputy Secretary-General Jan Eliasson said on Friday.

Damaged aid trucks are pictured after an airstrike on the rebel held Urm al-Kubra town, western Aleppo city, Syria September 20, 2016. REUTERS/Ammar Abdullah

The United States has said it believes two Russian aircraft carried out the strike near Aleppo, which killed 20 people, destroyed a warehouse and 18 trucks, and shattered a one-week truce. Russia has denied involvement.

U.N. Secretary-General Ban Ki-moon launched an independent board of inquiry into the attack, which U.N. satellite imagery experts have said was an air strike.

“We now have a three-person board of inquiry. And they are in the area, I believe, and were already a couple of days ago, even last week I think, and are working on it,” Eliasson told a news conference.

“Of course we know that it’s a difficult mission because it’s a mission where access is very difficult,” he added.

“We know of course that manipulation of evidence can take place and evidence can disappear and so forth.”

U.N. spokeswoman Alessandra Vellucci later clarified that it was a five-member team and that “they are not there yet, but we hope they will be there soon”.

Such an attack against a humanitarian convoy carrying food and medical supplies for civilians “constitutes without any doubt a war crime”, Eliasson said.

VETO POWERS

It was absolutely crucial to gather as much information as possible. “We would like to see as much as possible if we can identify who was behind this attack,” he said, adding that the results should be “out in the open”.

“This issue is an issue which probably will be of interest to bring to the Security Council and then we’ll see what happens in the Council,” he said.

The five permanent members of the Security Council - Russia as well as Britain, China, France and the United States - have veto powers, including against any move to send such a case to the International Criminal Court.

U.S. Secretary of State John Kerry said on Thursday he had discussed “all aspects” of the Aleppo conflict in a meeting with Russia’s Foreign Minister Sergei Lavrov.

Lavrov, speaking to reporters, denied Russia’s military was carrying out air strikes in rebel-held Aleppo this week.

U.N. aid workers have since July had no access to rebel-held eastern Aleppo, where 250,000-275,000 people live under siege by government forces and their allies. The last distribution of rations was a week ago.

“We are definitely running out of food and it’s a hugely critical situation,” Eliasson said.