The Trump administration, which has stepped up sanctions against the government of Nicolas Maduro, has not ruled out military action to remove what it and dozens of other nations consider an illegitimate government that rigged a 2018 election
The United States walked out of the Conference on Disarmament on Tuesday to protest against Venezuela assuming the rotating presidency of the UN-sponsored forum - as it did a year ago when Syria took the chair.
The Trump administration, which has stepped up sanctions against the government of Nicolas Maduro, has not ruled out military action to remove what it and dozens of other nations consider an illegitimate government that rigged a 2018 election.
As Venezuela took up the one-month presidency of the Geneva talks, US disarmament ambassador Robert Wood left the session and announced a "boycott" while Maduro ambassador Jorge Valero chairs it.
"We have to try to do what we can to prevent these types of states from presiding over international bodies," Wood told reporters.
"Clearly, when you have regimes like the (Bashar) Assad regime (of Syria) and the Maduro regime presiding over this body, there is something fundamentally wrong with how we are conducting our business. And we need to examine that," he said.
A representative of Venezuelan opposition leader Juan Guaido, the "interim leader", should assume the seat, Wood said.
Latin American delegations including Argentina, Brazil and Chile who also recognise Guaido stayed away from the Conference. Syria and Russia denounced what they called its politicisation.
Valero condemned the move.
"We regret that the representative of the United States and its docile allies continue to bring to this forum matters that are outside the mandate of the CD," he told a news briefing.
"It is not a forum for coup-mongering."
More than $4.5 billion in Venezuelan assets have been frozen or confiscated under US-led sanctions that are crippling vital imports of food and medicines, Valero added.
Maduro maintains control over Venezuela's state institutions, calls Guaido a puppet of Washington and blames US sanctions for a hyperinflationary economic meltdown and humanitarian crisis.