The United States has presented a draft resolution at the United Nations Security Council calling for international aid deliveries and a presidential vote in Venezuela, triggering a Russian counter-proposal.
While no date has been set for a vote on the American draft, and negotiations are ongoing, Russia is likely to use its veto power to block it as part of its support of Nicolas Maduro's regime, diplomats said.
The text expresses "full support for the National Assembly as the only democratically elected institution in Venezuela".
The legislative body's chairman, Juan Guaido, has declared himself interim president of Venezuela, challenging Mr Maduro's rule.
The draft resolution stresses "deep concern with the violence and excessive use of force by Venezuelan security forces against unarmed, peaceful protesters".
It also "calls for the immediate start of a political process leading to free, fair and credible presidential elections, with international electoral observation, in line with Venezuela's constitution".
The text also requests that UN Secretary General Antonio Guterres "utilise his good offices" to obtain such elections.
It "stresses the need to prevent further deterioration of the humanitarian situation in Venezuela and to facilitate access and delivery of assistance to all in need in the entirety of the territory of Venezuela".
On Friday, Moscow proposed an alternative resolution, diplomats said.
It expresses "concern over the threats to use force against the territorial integrity and political independence of … Venezuela", according to a draft.
The draft also criticises "attempts to intervene in matters which are essentially within the domestic jurisdiction of … Venezuela".
Calling for a "peaceful" resolution of the stalemate, it "supports all initiatives aimed at reaching a political solution among Venezuelans to the current situation … through a genuine and inclusive process of national dialogue".
However, a diplomat said that if put to a vote, the Russian text would fail to obtain the minimum of nine votes to pass without another veto-wielding country blocking it.
Humanitarian aid sent by the United States arrived in the Colombian city of Cucuta at the border with Venezuela, but Mr Maduro has refused to let in the shipments.
Mr Guaido said on Friday he was ready to take any necessary measures, including authorising a US military intervention, to force Mr Maduro from power and alleviate the humanitarian crisis.
