The confirmation of Ms Kathleen Troia "K.T." McFarland as the US ambassador to Singapore may be in limbo, reflecting turmoil in Washington triggered by the FBI's investigation into the Trump campaign's potential collusion with Russia during last year's US presidential election.
Ms McFarland told the Senate Foreign Relations Committee in written comments for her confirmation hearing in September that she "was not aware" of any communication between Mr Michael Flynn, a key figure in President Donald Trump's campaign who was later made national security adviser, and Russia's then Ambassador to Washington Sergey Kislyak.
But The New York Times reported on Monday that it had obtained an e-mail Ms McFarland sent on Dec 29 last year - the day former president Barack Obama's administration authorised new sanctions against Russia - saying Mr Flynn would talk to Mr Kislyak that evening.
Mr Flynn, a former lieutenant-general, pleaded guilty last Friday to lying to the Federal Bureau of Investigation about his contacts with Russia, and agreed to cooperate with prosecutors delving into the actions of Mr Trump's inner circle before he took office.
Maryland Senator Ben Cardin, the top Democrat on the Senate Foreign Relations Committee, told CNN: "I think there should be no action on (Ms McFarland's) nomination until we get the information."
Her appointment was due to go to a vote in the Senate, and it is unclear what will happen now. Reuters reported that Senate Majority Leader Mitch McConnell would have to take procedural steps in order to overcome the hold and confirm her nomination, which would eat up floor time in the Senate.
"It looks like a fraught nomination," Mr Ernie Bower, chief executive of consultancy BowerGroupAsia, told The Straits Times.
This may leave the United States without an ambassador in Singapore for some time.
"It is hard not to have an ambassador in the country chairing Asean," added Mr Bower. Singapore takes on the rotating chairmanship of Asean next year, and Mr Bower noted the US has not nominated an ambassador to Asean either.
The majority of US ambassadors posted abroad are career State Department officials, but about 30 per cent of them have been political appointees in recent years, especially to countries with which Washington has significant ties. US ambassadors to Singapore have been political appointees for the past three decades, since veteran diplomat J. Stapleton Roy left in 1986.
Delays in appointments to key posts abroad have raised eyebrows in Washington. The nomination for the ambassador to Seoul - speculated to be seasoned Korea hand Victor Cha - has also not been announced yet.
This is not the longest time that the US Embassy in Singapore has been without an ambassador. US Embassy spokesman Camille Dawson said it was aware of two previous instances when there had been gaps between ambassadors that extended beyond one year.
She cited the 15-month breaks from June 1993 to September 1994, when Ambassador Timothy Chorba took over from Ambassador Jon Huntsman following then President Bill Clinton's election, and from January 2009 to April 2010, when Ambassador David Adelman took over from Ambassador Patricia Herbold following Mr Obama's election.
Ms Dawson said Ms Stephanie Syptak-Ramnath will continue leading the embassy as charge d'affaires until an ambassador has been confirmed. "Relations between Singapore and the US continue to be excellent," she added.
"The US Embassy remains hard at work advancing the US-Singapore bilateral relationship based on mutual economic interests, robust security and defence cooperation, and vibrant people-to-people ties," Ms Dawson said.
She noted that Prime Minister Lee Hsien Loong's visit to Washington in October and Mr Trump's trip to Asia last month were "clear signals that President Trump and his administration are committed to our continued engagement with Singapore and the region".
Ms McFarland, 66, served as deputy national security adviser to Mr Flynn before he was fired in February, after it was revealed that he had misled Vice-President Mike Pence over the nature of his contacts with the Russian ambassador
•Additional reporting by Felicia Choo