UPDATE #1: Via a reader tip Yonhap has a picture that shows that bridge the vehicle apparently fell off was actually one of the small bridges on the training area:
A U.S. army vehicle fell into a river in northern South Korea during military training, killing two American soldiers, military and police officials said Friday.
Soldiers in a U.S. Army Humvee were taking part in a brigade field training exercise in the vicinity of the Rodriguez Live Fire Complex and fell into the Hantan River in Yeoncheon, Gyeonggi Province, on Thursday, the U.S. Forces Korea said.
Following the search throughout the night, the bodies of a major and a corporal were found near the river around 10:25 a.m., according to the authorities. [Yonhap]
You can read more at the link, but this accident happening on the training area itself is more likely than happening enroute because there are primitive roads and smaller bridges on the training area and it can get very dark out which makes navigation difficult if they were driving at night.
This is the first I have heard of anyone being killed during a convoy to Rodriguez Range:
Two soldiers from the 2nd Infantry Division were killed after their military vehicle went into a river near the Rodriguez Live Fire Complex in South Korea Nov. 21, Army officials confirmed.
The names of the soldiers are not being released until their families have been notified.
The soldiers went missing while they were driving to a training area during a brigade training exercise, according to a 2nd ID news release.
The soldiers were found after an overnight search that started late afternoon on Nov. 21 when their unit lost contact with the soldiers, the release said. [Army Times]
You can read the rest at the link, but I saw nothing about the accident posted on the 2ID website or the USFK website. It is however not unheard of to have fatal training accidents in Korea because I can remember some happening years ago along the Imjim River.
The S&S says the soldiers killed were a corporal and a major. There are a few rivers that have big bridges across them on the way to Rodriguez Range so it is not like there was primitive bridges they had to cross if the accident happened on the way to the range as reported. I am sure we will eventually hear what happened but condolences to all the families effected by this tragic accident.