(NBC NEWS)--Emergency crews were searching Friday for a man and woman who jumped into the icy waters of the Big Sioux River in South Dakota to try to save a six-year-old child, before being swept off by the raging current themselves.
The two adults jumped into the river near Sioux Falls around 6 p.m. local time on Thursday after the young boy fell in.
The woman is related to the child but not his mother, the man is not a relative of the boy, KDLT reported.
"By the time I got there he was already in there and they had him by the arm," Napoleon Ducheneaux, a friend of the man who dove in, told KDLT.
"They had the kid in his arm and he slipped and fell. And then not too long after that the kid popped up a little bit to the right and climbed up the rocks by himself," he added.
The two adults found themselves in trouble.
"I heard him and the woman talking. He said something like, ‘You hold on to me, I'll hold on to you.' And I kept telling them to come to my voice," Ducheneaux told KDLT.
The two then slipped under the water, Ducheneaux said.
Sioux Falls Fire Rescue Chief Jim Sideras confirmed two people were missing.
"We have some issues with very thick ice that we are trying to address. We also have a high flow of water because of ice melting," he said.
"We have a lot of foam. We have on the scene crews who are trained in swift water rescue and ice rescue. We also have on site a dive team. Because of the thickness of the ice it's not possible for that team to go in. We are still doing search patterns," he added.
Sideras told KDLT that the boy was safe with family members. "I was with him and he's with family members and he's doing fine," Sideras said.