US President Donald Trump has hinted that China played a part in bringing Iran to the negotiating table for a ceasefire, which was announced on Tuesday.
The ceasefire, which pauses the war for two weeks, is expected to reopen the Strait of Hormuz, a key route for global shipping.
Trump is set to visit China in May for talks with Chinese President Xi Jinping, and officials say China used its influence quietly to support talks.
Pakistan played a key role as an intermediary, while officials say China, Iran's largest trading partner, used its influence to support talks.
China has not confirmed any direct role, but its foreign ministry said it supported the ceasefire and had been working for peace.
China's interest in regional stability is tied to both energy security and trade, as the Strait of Hormuz is a key route for global oil supplies and any disruption affects major economies, including China.
