BRUSSELS, Belgium — Belgian Prime Minister Leterme’s four-month-old government collapsed after failing to heal a rift between French- and Dutch-speaking voters that may threaten to split the country.

King Albert II is considering the resignation Mr. Leterme submitted just before midnight Monday, the royal palace said in a statement yesterday in Brussels. Mr. Leterme’s coalition, which took a record nine months to pull together, fractured after missing a self-imposed July 15 deadline for getting an agreement on regional autonomy and on splitting a disputed voting district.

The resignation plunges the country into the worst political deadlock in its 177-year history at a time when the fastest inflation in almost 24 years is eroding Belgians’ purchasing power and slower economic growth threatens the budget. Consumer confidence dropped to a three-year low last month.

“We’re facing the worst financial and economic crisis since the end of World War II and nobody in Belgium seems to care,” said Mark Eyskens, a member of Mr. Leterme’s Christian Democratic Party who served in Belgian governments between 1976 and 1992 and was prime minister in 1981-82. “We need a government.”

The government’s collapse may prompt more concern that Belgium’s federation may fall apart, a prospect complicated by the fact that the capital of Brussels is surrounded by Flemish territory. The city of 1 million people hosts the European Union’s main institutions as well as the North Atlantic Treaty Organization.