Republican senators who recently returned from Moscow have some advice for President Donald Trump ahead of his meeting Monday in Helsinki with Russian President Vladimir Putin: Be prepared, be careful and try not to be alone.

“He better know the right Russian psyche,” said Senate Appropriations Chairman Richard C. Shelby. “All he’s got to do is start with Stalin and come on up and see what’s changed.”

The Alabama Republican led the delegation, which met with senior Russian officials, including Foreign Minister Sergey Lavrov.

Sen. Jerry Moran of Kansas, who was on the trip, said in an interview that he had particular concerns about the possibility of Russian media entities misreporting the outcome of any one-on-one meeting between Trump and Putin.

“They’re propagandists. When I read what the Russian press said that transpired in those meetings, I don’t know why — I don’t believe them when they say they weren’t involved in meddling in U.S. elections,” Moran said. “I don’t know why people would believe them when they say their description of the meeting.”