A U.S. airstrike took the lives of a number of Iraqi soldiers Friday, having been caused by "a mistake that involved both sides," said U.S. Defense Secretary Ash Carter.

Carter called up Iraqi Prime Minister Haider al-Abadi and expressed his condolences and said that the incident has been a regrettable one. Speaking aboard the USS Kearsarge in the Persian Gulf, Carter said that the airstrike "has all the indications of being a mistake of the kind that can happen on a dynamic battlefield."

The Kearsarge is an amphibious assault ship supporting the coalition militants in Iraq and Syria against the Islamic State. Carter had spent two days in Iraq in the past week and had also spoken to the al-Abadi from the USS Kearsarge, according to Fox News.

While Carter did not offer any detailed explanations over the series of events that incurred, an American official, under anonymity, said that the plane which carried out the attack was a B-1B. It had dropped several bombs upon IS near Fallujah, out of which one of those bombs had struck the Iraqi troops as well. Another American official said that the weather had played an important factor in the miscalculations of the bomber, as the Iraqi officials appeared to be closer to the area than they had first anticipated. The Iraqi militants had advanced forward after the first two bombs were dropped when they were struck by the third since the Americans didn't realize that the troops had moved forward, The New York Times reported.

Saad Maan, an Iraqi Brigadier, said that nine soldiers and one officer died because of the strike. This incident marks the first time that the Americans have acknowledged that one of its airstrikes had struck the Iraqi forces by accident, according to The Wall Street Journal.