WASHINGTON • Mr Sergey Kislyak, Russia's long-serving ambassador to the United States, has a habit noticed by many US officials who have known the envoy.
He shows up everywhere and tries to talk to everyone.
"He does not get as much credit as he should, in my view, for being savvy about developing relationships with people all over the city," said Mr Michael McFaul.
He knew the diplomat well while serving in the Obama administration as senior adviser on Russia and then as US ambassador to Russia.
Moscow's man in Washington, DC, is an unlikely man of the political moment, however. He is quiet, careful, rumpled and portly. He is a fierce defender of Russia's international prestige who rarely gives interviews and even more rarely makes news on his own. He is not considered especially close to Russian President Vladimir Putin.
For Mr Kislyak to have sought contacts with former national security adviser Michael Flynn and Attorney-General Jeff Sessions last year when the latter was a US senator should come as no surprise, current and former US officials said.
Mr Flynn, a retired army lieutenant-general and former head of the Defence Intelligence Agency, was a top national security adviser and frequent warm-up act for President Donald Trump during the campaign. He was forced out as national security adviser at the White House over concerns he had misled Vice- President Mike Pence and others about his contacts with Mr Kislyak before Mr Trump took office.
Mr Sessions, then a US senator from Alabama, was among Mr Trump's early supporters in Congress and went on television to promote the candidate. He has come under scrutiny for two meetings with Mr Kislyak last year.
The Russian diplomat, who speaks excellent English, seems to know American officials, past and present, across the political and ideological spectrum. Several Americans who know him said he prides himself on proximity - he always seems to have just had dinner with someone influential or just happens to be seated up front at newsworthy foreign policy events.
Mr John McLaughlin, a former deputy Central Intelligence Agency director and acting CIA director under former president Barack Obama, said "it does strain credibility" that Mr Sessions would have simply forgotten about his meetings with Mr Kislyak when he asserted during his confirmation hearing to become attorney-general that he had not met Russian officials.
Mr Sessions said at a news conference on Thursday that he was "taken aback" by a question - which referred to a breaking news story about contacts between Trump campaign surrogates and Russians. "In retrospect, I should have slowed down and said I did meet one Russian official a couple of times. That would be the ambassador," he said.
Mr Kislyak arrived as ambassador in 2008, a few months before the start of the Obama administration, and is expected to leave this spring. His replacement has not been announced.
"It seems entirely routine for the ambassador of a foreign government to want to meet with senators, for example, and especially one who is a member of the Armed Services Committee," said Mr Paul Saunders, a Russia specialist at the Centre for the National Interest and a former official in the George W. Bush administration.