MOSCOW: Michael McFaul, the outspoken US ambassador to Russia who has frequently ruffled feathers in Moscow, announced Tuesday he would be leaving the country after just two years.
His announcement that he would also leave the US administration comes amid a new spike in tensions between Moscow and Washington over a litany of issues ranging from arms to human rights to pro-Western protests in Ukraine.
An embassy spokeswoman confirmed that McFaul was leaving Russia "early" but declined to comment further.
A professor of political science on leave from Stanford University, McFaul, 50, said he was leaving for family reasons.
"Soon after the Olympics, I plan to rejoin my family in California," McFaul wrote on his blog, adding that it was important for him to be reunited with his wife and two sons.
The Winter Olympic Games are set to begin in the Black Sea resort of Sochi on Friday and will run through February 23.
"After more than five years of working in President Obama's administration the time has come to return home."
Many said Washington had taken a risky bet by appointing a non-career diplomat as its ambassador to Russia in January 2012.
Dubbed the "undiplomatic diplomat," McFaul frequently sparked Moscow's fury with critical comments and meetings with Russian opposition activists.
"Goodbye, Mikhail!" the official Twitter account of the Russian foreign ministry said in a conspicuously curt reaction, using the Russian version of his first name.
McFaul, who studied in the Soviet Union, has reached out to young Russians with blog posts in their native language.
In his last post as ambassador, he said scores of Russians across the country had taken a keen interest in meeting him.
"Thousands of Russians came to discuss with me everything from Syria to my broken finger."
'He irritated many'
Before taking over as ambassador, McFaul helped reset Russia-US relations following Russian strongman Vladimir Putin's departure from the Kremlin in 2008.
Relations between Moscow and Washington deteriorated sharply after Putin returned for a third term in 2012.
Analysts had interpreted attacks on McFaul by Russian state media and lawmakers as part of a blunt Kremlin message to Washington that it should keep the tone of its criticism muted.
In one notable run-in early on, McFaul came under fire from Russia's parliament for meeting the leaders of anti-Putin protests during his first week on the job in 2012.
"McFaul irritated many in our political circles," said foreign policy observer Maxim Yusin.
"He was in contact with our opposition and it was looked upon negatively," said Yusin who writes for the Kommersant broadsheet.
"I believe that our officials let their displeasure be known to their US colleagues during meetings."
An average US ambassador's tenure in Moscow usually lasts around three years.
Putin, who returned to the Kremlin on a wave of anti-US rhetoric, has repeatedly accused Washington of imposing its will on other nations and preaching on human rights.
Two months of pro-EU protests in ex-Soviet Ukraine has become another bone of contention, with Washington and Brussels supporting the opposition demonstrators and the Kremlin publicly backing embattled President Viktor Yanukovych.
In Washington, the US National Security Council said President Barack Obama was "deeply grateful" to McFaul.
"Mike has been tireless in advocating for the universal values that America stands for around the world," the council said.