Sen. Charles Schumer on Sunday said Vladimir Putin is "behaving like a school yard bully," adding that President Obama should cancel a planned summit with the Russian president next month.

(Alexei Nikolsky/AFP-Getty Images) (Alexei Nikolsky/AFP-Getty Images)

"Unless you stand up to that bully, they ask for more and more and more," Schumer said on CBS's "Face the Nation". "Always going out of his way, Mr. Putin is, to poke us in the eye with Iran and Syria, now with [Edward] Snowden."

Last week, Putin granted temporary asylum to Snowden, a former National Security Agency contractor who leaked top-secret information about a controversial electronic-surveillance program. Lawmakers from both sides in Congress have called for a rethinking of relations with Moscow because of the Russian president's actions.

“The relationship between the United States and Russia is more poisonous than at any time since the Cold War because of all of this,” Schumer said.