ROME — Italy pledged today to work swiftly for a constitutional amendment requiring the government to balance its budget, as Rome feverishly tried to assure domestic and foreign investors its finances are sound and calm nervous markets in Europe.

Premier Silvio Berlusconi told a hastily convened evening news conference the government will “speed up measures” in its budget law approved last month by Parliament, “with the possibility of reaching a balanced budget by 2013 instead of 2014” as first planned.

His conservative government, now more than three years into its five-year term, will also work to amend the Constitution to include a requirement for a balanced budget, Berlusconi said.

Berlusconi, saying he conferred by phone with world leaders, announced that G-7 finance ministers will meet “within days” about the exploding financial crisis.

Later, his spokesman clarified that convening an “extraordinary meeting” of the G-7 finance ministers was still “at the reflection stage” with no decision yet taken, although Italy favored one.