PELLA, Iowa — Sen. Chuck Grassley, R-Iowa, introduced Republican presidential front-runner Donald Trump Saturday with a call for party unity and against the 2016 Democratic presidential field.

Notably, Grassley mentioned Trump by name once during his address to the real estate mogul's supporters and did not offer up any hint of a forthcoming endorsement — having remained neutral throughout the process.

"I want Mr. Trump to know that I appreciate his support for me," Grassley said opening his speech.

However, the longtime Iowa political stalwart did tell the sold-out crowd that voters have the "opportunity to make America great again." He also peppered his speech with criticisms of President Obama, calling him out for his executive actions on immigration and, more recently, on gun control.

"I'm excited to see the big crowds because of the big energy that comes with it and we've got to keep up this energy that's shown here today and many other places around Iowa because that is what is going to take for us to win back the White House in November," Grassley said.

Opening up his address, Trump offered up praise for Grassley, who has served in the U.S. Senate for 35 years.

"This is a great guy — respected by everybody," Trump told the crowd. The real estate mogul also threw out plaudits for Gov. Terry Branstad, who recently urged Iowans to not vote for Sen. Ted Cruz.

"You have a great governor," Trump said.

Trump is currently second in the Washington Examiner's presidential power rankings.