ROME — Prime Minister Enrico Letta said that he would call for a confidence vote in Parliament, most likely on Wednesday, to clear up the political uncertainty surrounding his fragile government after the sudden resignation of five ministers belonging to Silvio Berlusconi’s center-right party.

In the vote, “everyone will assume their own responsibility, all above board,” Mr. Letta said on Italian television Sunday night, shortly after meeting with President Giorgio Napolitano to discuss the government crisis prompted by the walkout.

The unexpected move on Saturday by Mr. Berlusconi’s allies raised concerns that Italy’s troubles may threaten the current political and financial stability in Europe. Political commentators speculated gloomily over the weekend about how the financial markets would react on Monday.

Mr. Letta also made clear that he would no longer be bound by the whims of Mr. Berlusconi’s People of Liberty party, which has been a mainstay of Italy’s broad coalition government, formed five months ago after elections in February failed to produce a clear majority.