President Obama said Russian President Vladimir may have “additional plans” in Ukraine and called on him to pull back his troops stationed along the border in an interview that aired Friday.

“It’s well known and well acknowledged that you’ve seen a range of troops massing along that border under the guise of military exercises. But these are not what Russia would normally be doing. And, you know, it may simply be an effort to intimidate Ukraine or it may be that they’ve got additional plans,” Obama said in the interview on “CBS This Morning.”

Russia must “de-escalate” and “move back those troops to begin negotiations directly with the Ukrainian government,” Obama said.

“CBS Evening News” host Scott Pelley interviewed Obama during the third leg of his overseas trip in Rome on Thursday.

The president’s comments come as nearly 100,000 Russian troops were reported to have lined up along Ukraine’s border on Thursday, a Ukrainian official told Agence France-Presse.