Several people were killed early Friday afternoon in a multi-vehicle crash on an Alabama highway.

According to the Alabama Law Enforcement Agency, the crash happened on U.S. 231 in Montgomery County, which remained closed as of 6:20 p.m. ET, according to WSFA 12.

According to WFSA, which has a news crew on the scene, several 18-wheelers are possibly involved. A medical helicopter and multiple first responders are on the scene.

An investigation is underway to determine the cause of the crash that has claimed at least two lives, WFSA reported. The Alabama Law Enforcement Agency has not released the actual number of deaths, only that there are multiple fatalities. Other injuries are also unknown, the news outlet reported.