The primary goal of the trip is to secure investment deals from Gulf states that would support economic initiatives in the US.
Witkoff's remarks come just days before Trump’s scheduled visit to Saudi Arabia, the United Arab Emirates, and Qatar next week.
Last week, Trump said the current nuclear talks between his country and the Islamic Republic were going "very well."
Marco Rubio said Iran must stop enrichment, missile development, and terrorism support, and allow US inspectors. Nuclear talks were postponed amid major US-Iran disagreements.
Trump has threatened to attack Iran unless it agrees to a new nuclear deal. Iran has far exceeded the 2015 agreement's curbs on its nuclear program since the United States withdrew.
Israeli officials have long vowed to prevent Tehran from acquiring nuclear weapons, an assertion Netanyahu repeated.
In a TIME interview, Trump predicted Saudi Arabia would join the Abraham Accords and discussed the possibility of military action against Iran.
The current rounds of negotiations with the US are not signs of a change of heart on the part of the Iranian regime or its supreme leader. They are a calculated survival tactic.
Iran and the US held a second round of talks in Rome, with plans to continue next week, as Tehran seeks a 'comprehensive' deal and maintains strong ties with Russia.
Iran told the US in talks it was ready to accept some limits on its uranium enrichment but needed watertight guarantees Trump wouldn't ditch another nuclear pact.