0111 GMT September 18, 2019
Antonov, whose appointment was announced on Monday, takes the job at a time when US-Russia relations are badly strained following the approval of a new wave of US sanctions against Moscow, and the Kremlin's decision to sharply cut American diplomatic personnel in Russia, , ALJAZEERA reported.
Antonov succeeds Sergei Kislyak, who found himself at the center of controversy amid claims of Russia's interference in the US presidential vote.
Kislyak's contacts with members of Trump's team have been part of congressional and FBI investigations into possible collusion between the Trump campaign and Russia.
Russia has denied any interference in the US election.
As a long-time diplomat, Antonov has the reputation of being a tough negotiator with a deep suspicion of Washington. But he is also a seasoned pragmatist able to adapt to sudden shifts in relations with the West.
He led negotiations on various international agreements, including the 2010 New start nuclear arms reduction treaty signed by the US and Russia.
In 2011, Antonov left the foreign ministry to become a deputy defense minister in charge of international ties.
When Russia-West relations sank to post-Cold War lows over the Ukrainian crisis and the war in Syria, Antonov's visibility earned him a hawkish reputation.
Like other senior Russian officials, Antonov backed Moscow's annexation of Crimea and supported pro-Russia armed groups in eastern Ukraine.
Antonov accused the West of engineering the overthrow of Ukraine's former Russia-leaning president in February 2014 as part of efforts to ‘contain’ Russia and waging what he described as an ‘information war’ against it.
He also claimed that Western countries had fueled the Ukrainian crisis in order to justify NATO's existence and budget.
The EU and Canada have put Antonov on their lists of Russian officials sanctioned for their role in the Ukrainian crisis.
Antonov also served as the Russian military's public face on Syria, where Moscow has waged an air campaign in support of President Bashar al-Assad's army.
Antonov's stint at the defense ministry ended in 2016, and he returned to the foreign ministry, taking the post of a deputy minister. He has largely stayed out of the public eye since then.
In May, when he met legislators who considered his candidacy for the ambassador's job, Antonov was quoted as saying that Moscow and Washington should normalize ties and engage in constructive cooperation.
He said the US and Russia must pool efforts in the fight against armed groups and work together to strengthen nuclear non-proliferation.
Kommersant daily had reported that Antonov was being lined up to move to Washington before Trump's surprise election victory over Hillary Clinton.