Chinese and Russian companies are developing an attack drone similar to an Iranian model deployed in Ukraine, European officials familiar with the matter said, a sign that Beijing may be edging closer to providing the sort of lethal aid that western officials have warned against.

The companies held talks in 2023 about collaborating to replicate Iran’s Shahed drone, and started developing and testing a version this year in preparation for shipment to Russia, said the officials, who asked not to be identified to discuss private information. The Chinese drones have yet to be used in Ukraine, they said.

Providing Russia a Shahed-like attack drone would mark a deepening of Beijing’s support for Russia despite repeated warnings from the U.S. and its allies. Chinese President Xi Jinping has sought to portray China as neutral in the conflict in Ukraine even as western officials say it’s provided components and other support for Russian President Vladimir Putin’s forces.