The US has also been trying to keep oil tankers moving through the Strait of Hormuz. American officials believe this has reduced some of the immediate pressure to reach a ceasefire agreement.
A UN-backed inquiry has found reasonable grounds to believe US forces committed war crimes during two February strikes in Iran, including a primary school bombing in Minab.
The US Central Command (CENTCOM) said an American warship had successfully avoided two ballistic missile attacks launched by Iran over the past two days.
An Iranian tanker was hit by four U.S. missiles near the critical Kharg Island oil export hub in the Gulf, Iranian state-linked media reported on Saturday.