The USS Lassen sailed close to a Chinese manmade island on Tuesday. Tensions have been mounting over China's territorial claims in the area.
China has criticized the sail-past of a US warship close to an uninhabited reef in the South China Sea that China has occupied. The US and others contest China's territorial claims there.
China has constructed islands in an area claimed by some of its neighbors. It says it has an exclusion zone around these islands, which is at odds with the US position.
Journalists, lawyers, and religious minorities have all raised concerns over China's crackdown on civil society. President Xi is making his first state visit to Washington this month.