A Russian cargo plane crashed soon after taking off from Juba, South Sudan, on Wednesday morning, killing at least 36 people.

The Associated Press reports the Soviet-made Antonov An-12 plane was headed to the country's Paloich oil fields, when it went down because of added load due to unregistered passengers aboard.

According to South Sudan's minister for transportation, Kuong Danhier Gatluak, 36 people were killed in the crash, though it is unspecified if all the victims were passengers on the plane.

The South Sudan Red Cross tweeted that 35 bodies were pulled from the wreckage.

Six of the flight's crew members, one Russian and five Armenians, were killed.

Two passengers were reportedly rescued from the plane wreckage. One later died, while the other, an infant, is currently in critical condition.

There are conflicting reports about exactly how many passengers were onboard. CNN reported earlier that there were 18 people on the flight total, but Gatluak said officials had not located the flight manifest.

Officials are also attempting to locate the plane's black box, in order to determine exactly what happened on the plane.

According to AP, a presidential spokesperson said 10 people on the ground were killed by the crash, but witnesses contradicted this information, saying there was no one at the site where the plane crashed.

Officials say there may be more bodies to be found still.

"We need heavy machinery to lift up to find out if there are other dead bodies under the wreckage of the plane," said Gatluak.

Antonov, the Ukraine-based aircraft company that built the plane, said the plane was in "no state to fly."

"The An-12B was is no state to fly because it failed to undergo timely technical servicing ... that should have included work on extending its resources and exploitation timeframe," said the company in a statement, via AFP.