Officials have confirmed reports of a United Nations helicopter being shot down by a rebel commander in South Sudan, killing three individuals.

The helicopter reportedly crashed just after 8 a.m. EST Tuesday, or 3 p.m. local time, and officials were initially unable to confirm reports that it was shot down, according to The Associated Press.

The U.N. mission tweeted that an Mi-18 cargo helicopter crashed near Bentiu, and search and rescue crews were being sent to the site.

Rebel commander Peter Gadet was responsible for shooting down the helicopter with a rocket-propelled grenade, Akol Ayom Wek, the press secretary for the governor of Northern Bahr el-Ghazal state, a region loyal to President Salva Kiir, told the AP.

Wek also told the AP that three bodies were found at the crash site, but the deaths have not been confirmed nor has there been any confirmation on the number of individuals on board the helicopter.

At a noon briefing, streamed live via the U.N., the helicopter attack was addressed.

A UN Secretary-General spokesperson, Stephane Dujarric, confirmed that the three who were found dead were part of the UN mission, and were Russian citizens.

There was a surviving member who was treated at a hospital in Bentiu, Dujarric said.

The helicopter was on a routine cargo flight when it lost contact with the UN and crashed, he said. All the individuals on board were Russian and the helicopter was contracted from a Russian company.

The incident is tragic but not entirely unexpected.

Gadet issued a threat that he would shoot down any U.N. planes, according to AP.

In addition, the area has seen widespread violence between the government and rebel forces since December.

The issue has escalated and brought up other issues that had been previously addressed, like the use of child soldiers in battle.

The government has reportedly been using child soldiers, whom they claim approached the military bases for work and shelter, according to a recent Human Rights Watch report.