The Venezuelan government said it received $735 million during the first day of a presale of its new oil-backed cryptocurrency, the "petro," as it seeks funds to revive its collapsing economy.

"We're off to a great start, a huge victory," said President Nicolás Maduro in a news release, announcing the sale of the tokens, each backed by a barrel of crude oil. The government aims to sell 100 million tokens for about $6 billion by March 19.

The sale comes after the country was declared in selective default by rating agencies including S&P Global Ratings in November 2017 for failing to make payments on bonds. The Venezuelan economy contracted by an estimated 36% cumulatively over the last four years, and is set to shrink by a further 14% in 2018, according to Fitch Ratings, which said inflation ended 2017 at 2,616%.

Venezuela's opposition has condemned the sale of the petro, branding it a mortgaging of the country's oil supplies, and the U.S. has warned that those buying the tokens could violate sanctions which the government in Caracas blames for the country's economic problems. Maduro is seeking re-election in a vote by the end of April, despite severe shortages of food and medicine and accusations of abuses by human rights groups.

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