Venezuela's Maduro says may go to US to challenge Obama

With Venezuela also demanding that the United States slash its Caracas embassy from 100 to 17 staff, the dispute has dominated local headlines and overshadowed an economic crisis.

Opposition leader Henrique Capriles accused Maduro of using the spat as a smokescreen. "Inflation through the roof. Scarcities too. Murders and poverty up. And the shameless rulers talking to us of an invasion," he tweeted.

Venezuela's opposition coalition has sought to disassociate itself from any perception of supporting outside meddling, while supporting the allegations of repression and graft.

Allies from Russia to Argentina have sent messages of support to Venezuela, as has the South American regional bloc UNASUR, while critics of US foreign policy have protested.

"Venezuela is one of the very few countries with significant oil reserves which does not submit to US dictates," wrote Glenn Greenwald, the journalist who first published documents leaked by fugitive former US spy contractor Edward Snowden.

"Such countries are always at the top of the US government and media list of 'Countries To Be Demonized'," he said.

Whipping up nationalist sentiment, Maduro addressed an "anti-imperialist" march on Thursday, while at the weekend the National Assembly is expected to grant him special decree powers he says are needed after the US moves.