The United States military is sending an additional 1,000 troops to the Middle East as tensions build with Iran.
Acting Defence Secretary Patrick Shanahan said the deployment was in response to what he described as “hostile behaviour” by Iranian forces.
The US Navy also shared new images it says links Iran to recent oil tanker attacks in the Gulf of Oman.
Iran announced on Monday it would no longer comply with part of the 2015 deal on curbing its nuclear ambitions.
It said it would breach a limit agreed with international powers on its enriched uranium stockpiles by June 27.