Former US ambassador to Russia blasts Trump's Putin praise

Michael McFaul, a former U.S. ambassador to Russia, blasted Republican presidential nominee Donald TrumpDonald John TrumpSarah Huckabee Sanders becomes Fox News contributor The US-Iranian scuffle over a ship is a sideshow to events in the Gulf South Korea: US, North Korea to resume nuclear talks 'soon' MORE on Twitter Friday for saying that Russian President Vladimir Putin has been a better leader than President Obama.

Trump and his running mate Mike PenceMichael (Mike) Richard PenceIceland's prime minister will not be in town for Pence's visit Trump's latest plan to undermine Social Security Nikki Haley voices 'complete support' for Pence MORE praised the Russian leader as "stronger" than Obama, citing his polled approval rating as evidence.

McFaul, who served as the ambassador in Moscow from 2012 to 2014, also slammed Trump for fawning over an authoritarian leader.

The former ambassador has been an outspoken critic of the real estate mogul, arguing that a Trump presidency would be in the Kremlin’s best interest.

Trump has struggled to put to bed claims that his campaign is too close to Russia's interests, criticism that found new life Thursday evening, when he gave an interview on a TV station owned by the Russian government.