"Special Representative Hook will travel to Estonia and the United Kingdom on July 28-29 for consultations with our European allies," the statement said on Monday.
The State Department said Hook met with high-level officials in Qatar and Kuwait over the weekend to discuss extending the UN arms embargo on Iran, which is scheduled to expire on 18 October.
In June, the United States introduced a draft resolution at the UN Security Council to extend the United Nations arms embargo on Iran before it expires. However, Russia and China have voiced their opposition to the draft resolution.
In 2015, Iran signed a nuclear agreement with China, France, Germany, Russia, the United Kingdom, the United States, Germany and the European Union. The agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA), stipulates that Iran must scale back its nuclear program and downgrade its uranium reserves in exchange for sanctions relief, including the lifting of the UN arms embargo five years after the accord was adopted.