Italy on Monday blocked a joint EU position to recognize Venezuela's opposition leader Juan Guaido as interim president, diplomatic sources said, with the government in Rome deeply divided over the issue.
Guaido said in a newspaper interview published on Monday he would do all he could to secure Rome's backing, but Italy's coalition parties took opposing positions.
Alessandro Di Battista, a prominent figure in one of them, the 5-Star Movement, said: "Handing out ultimatums, sanctions, freezing Venezuelan goods ... It would mean opening the road to a military intervention.
"The 5-Star Movement and this government will never recognise people who appoint themselves president."
The other coalition party, the far-right League party, has come out strongly in favour of Guaido and acknowledged that attempts to find common cause with 5-Star had so far failed.
"Our (coalition) allies think we need to act gradually and be more prudent," League head, Deputy Prime Minister Matteo Salvini, told Rete 4 television. "We're not looking very good on this."
European Union states have been debating for days how to address the Venezuela crisis, with 11 countries on Monday recognizing Guaido after President Nicolas Maduro ignored their demand to call a new election.
But Italy blocked the draft EU statement.
Guaido told Corriere della Sera newspaper that the only way Venezuela could emerge from the crisis was via "radical change" and said he hoped Rome would back him.
"We'll do everything possible so that the Italian government adds its support - which is very important for us - to that expressed by the rest of the European Union," he was quoted as saying.
Venezuelans of Italian origin are a large and influential group in the South American country.
Italian President Sergio Mattarella, who plays a mainly ceremonial role and usually stays out of day-to-day politics, urged the government to overcome its differences and back Guaido.
"We must demonstrate responsibility and clarity with a common line taken by all our EU partners and allies," Mattarella said at an event in Rome on Monday.
Mainstream center-left and center-right opposition parties denounced the government for being out of step with major EU partners.
"I think the day will come when (the government) will be ashamed of having been on the wrong side of history. I stand alongside our co-nationals, against dictatorship and for freedom," former prime minister Matteo Renzi said on Twitter.