Madison, Alabama (CNN) Sen. Jeff Sessions on Sunday became the first sitting senator to endorse Donald Trump, declaring his support for the Republican front-runner during a rally at a football stadium here.

The endorsement from the Alabama Republican known for his opposition to illegal immigration will solidify Trump's attempts to position himself as the Republican presidential candidate with the toughest stance on the issue.

The endorsement comes two days before the crucial Super Tuesday primary when Alabama and a dozen other states, mostly in the South, vote.

"At this time in American history we need to make America great again," Sessions told the raucous crowd as he donned one of Trump's signature caps emblazoned with that campaign slogan. "I am pleased to endorse Donald Trump for president of the United States."

"A movement is afoot that must not fade away," Sessions added.