Satellite imagery and intelligence support provided by Chinese groups have helped Iran threaten ships in the Strait of Hormuz and launch precision strikes on US military bases in the Middle East, part of a dramatic improvement in Iranian targeting capabilities over the past several months, according to a series of recent American intelligence assessments described to CNN by four sources.

The imagery allowed Iran to strike a US base in Jordan in July, a strike that killed three American service members, with a level of precision US officials believe was otherwise beyond Iran’s capabilities, the sources said.