MOSCOW — Ukraine won a new lending commitment from the International Monetary Fund on Tuesday, a lifeline from the West for a country whose economy has been sapped by corruption and war with Russian-backed separatists.

The new loan is a boon for President Petro O. Poroshenko ahead of a presidential election scheduled for March. He announced the decision on his Facebook page and the I.M.F. described the program in a statement.

Without the new support, it was unclear how the government would pay internal and external debt and finance a budget deficit, as the I.M.F. had suspended an earlier bailout over worries about corruption. A year after Mr. Poroshenko’s pro-Western government came to power in 2014, the I.M.F. agreed to loan Ukraine $17.5 billion over four years — and then suspended the aid in 2017 after disbursing half.

Before the new loan was announced, Ukraine had seemed headed toward default with $11 billion in debt coming due within two years.