Countries were supposed to give their agreement for the plan to go ahead by written procedure on Monday evening by 8 p.m. The deadline was extended to 8:30, per two diplomats granted anonymity to speak freely, and then again to 10 p.m. The negotiations were finally pushed until 8 a.m. Tuesday, one of the diplomats said.

France cited “national security concerns” in justifying its demand, joining forces with Slovakia, which has long lobbied for Usmanov’s delisting. Luxembourg, meanwhile, has long called for the delisting of the Ukrainian-born, Russian-Israeli tycoon Fridman, who is suing the country for the release of frozen assets.

France has declined to provide more detail on its motivations publicly or privately. Diplomats said only that the move relates to “a specific national security issue” and that Paris “wishes to respond positively to international partners who have approached us regarding Mr. Usmanov.”

Usmanov has consistently denied supporting Russia’s war effort and campaigned for his removal from the sanctions list, while Fridman has argued the seizure of his assets is unlawful.

This article was updated to reflect that the deadline for the end of talks was extended. Koen Verhelst and Joe Stanley-Smith contributed to this report.