Canadian Prime Minister Justin Trudeau, responding to Iran’s statement that a missile shot down a Ukrainian airliner this week, said on Saturday that his government sought a full investigation and full cooperation from the Iranian authorities.

All 176 people on board, including 57 Canadians, were killed in Wednesday’s crash after take-off from Tehran. Canada had said for several days it believed the plane was downed by an Iranian missile, but until Saturday Iran had denied this.

In a statement issued by his office, Trudeau said that Iran had now acknowledged that the plane was brought down by its own armed forces.

“Our focus remains closure, accountability, transparency, and justice for the families and loved ones of the victims. This is a national tragedy, and all Canadians are mourning together,” he said.

“We will continue working with our partners around the world to ensure a complete and thorough investigation, and the Canadian government expects full cooperation from Iranian authorities.”