Russia made a surprise proposal Monday to restructure Ukraine’s $3 billion debt coming due next month, offering a potential solution to a standoff that has threatened to complicate an international bailout of Ukraine.

Speaking on the sidelines of the G20 summit in Antalya, Turkey, Russian President Vladimir Putin said Moscow proposed that Kiev repay $1 billion of its debt each year from 2016 to 2018, and be freed from all payments this year.

Russia...