A leading Republican voice on national security matters is declaring as "unacceptable" any attempt by the incoming Trump administration to reset relations with Russia.

In a statement Tuesday, Sen. John McCain of Arizona says the price of starting anew with Moscow would be U.S. complicity in the "butchery of the Syrian people" being carried out by Russian President Vladimir Putin and Syrian President Bashar Assad.

President-elect Donald Trump and Putin spoke Monday to discuss future efforts to improve the U.S.-Russian ties. Trump said in a statement that he is looking forward to having a "strong and enduring relationship with Russia."

McCain, the Armed Services Committee chairman, dismissed Putin as a former KGB agent who has plunged his country into tyranny and murdered his political rivals and threatened U.S. allies.