Three people are dead after a pickup truck crossed a median and collided with a semi north of Maricopa Wednesday afternoon, Arizona Department of Public Safety officials said.

All three of the people killed in the crash -- two men and a woman, all in their 20s -- were inside the pickup, and another man from inside that vehicle was taken to the hospital.

The crash happened around 3:20 p.m. on northbound State Route 347 at Casa Blanca Road after the truck crossed from southbound traffic. It's not clear what caused the truck to cross the median.

The right lane is closed on SR 347 while authorities work.