A minivan carrying 12 people skidded off an icy highway early Sunday and slammed into an oncoming tractor-trailer, killing seven, the Oklahoma Highway Patrol said.
 
 The eastbound van slid through the center median and struck a westbound tractor-trailer around 3:50 a.m., trooper Kera Philippi said. Five of the van's occupants were taken to a hospital, Philippi said.
 
 The identities of the victims were not immediately released.
 
 Philippi said all the van's occupants were residents of Mexico