Venezuelan President Nicolas Maduro on Thursday said he had signed deals with Russia worth six billion dollars during a recent visit to Moscow.

The deals include investments in the oil sector and gold mining, Maduro tweeted.

The socialist president also said he had purchased 600,000 tonnes of wheat for the coming year.

His tweet also spoke of "Alliances for the people's happiness!"

Despite its vast oil reserves, Venezuela is suffering an economic, political and humanitarian crisis, with widespread shortages of basic goods and skyrocketing inflation.

Some three million people have left the country, according to United Nations agencies, more than one million of them to neighbouring Colombia.

Peru, Ecuador, Argentina, Chile, Brazil and Panama also host large numbers of Venezuelan refugees.

The South American country has become increasingly isolated amid international criticism of the Maduro regime.