"Great move on delay (by V. Putin) - I always knew he was very smart!" Trump tweeted.
Earlier, the Russian leader ruled out any immediate tit-for-tat expulsions of American officials in the row over what Washington says were "efforts to harm US interests" in connection with the November 8 election won by the Republican.
Putin's own foreign ministry had recommended that he eject 35 American officials to counterbalance US President Barack Obama's move yesterday to expel 35 Russian intelligence operatives and shut down two Russian compounds in the US.