"We certainly don’t have any information to suggest that the crash was anything but accidental. We support a full investigation and full transparency concerning what happened to the aircraft," State Department deputy spokesman Adam Ereli said at a briefing.
Ereli said that at the request of Uganda and Sudan, the United States has agreed to assist with the investigation.
"We’ve got a five-member team of the National Transportation Safety Board that arrived in Nairobi on Friday and is today on route to the site of the crash where they’ll begin their investigation," he said.
"But again, as far as we’re aware, the crash was accidental," he added.
Garang and 13 others were killed on July 30 when Ugandan President Yoweri Museveni’s Russian-made Mi-172 helicopter in which they were taking to return to Sudan from Uganda crashed in the hills of southern Sudan.
Garang, a former southern rebel leader, was sworn in as first vice president only on July 9