Saudi Arabia privately hinted earlier this year it might sell some European debt holdings if the Group of Seven decided to seize almost $300 billion of Russia's frozen assets, people familiar with the matter said.

The kingdom's finance ministry told some G-7 counterparts of its opposition to the idea, which was meant to support Ukraine, with one person describing it as a veiled threat. The Saudis specifically mentioned debt issued by the French treasury, two of the people...