Obama on Tuesday strongly criticized Trump for praising Russian President Vladimir Putin and for appearing on a TV channel, RT, funded by the Russian government.
"Unfortunately, we see continued displays of often hard-core Russophobia," Kremlin spokesman Dmitry Peskov, commenting on Obama's intervention, told a conference call with reporters. "We can only express regret in this regard."
"This rhetoric, which is being formulated in electoral campaign style ... is unlikely to help fledgling fragile attempts to build at least some sort of mutual trust," Peskov added.