Tillerson spoke on Tuesday at the Kuwait International Conference for Reconstruction of Iraq in Bayan, a city in Kuwait.
He started his trip on Sunday by visiting Cairo, Egypt, a trip through the Middle East as he faces confrontational talks at almost every stop on his five-country tour.
A key US ally, Israel, is conspicuously absent from his itinerary.
This is while Saudi Arabia, the UAE, Bahrain, Egypt, Libya, and several other countries cut off diplomatic ties with Qatar in June over allegations that Doha is sponsoring terrorism and destabilizing the region.
Qatar has vehemently denied the accusations, calling them unfounded.
Qatar, home to the forward headquarters of the US military's Central Command and some 10,000 American troops, had assigned some of its US-provided fighter jets to the unprovoked war, which has killed over 12,000 Yemeni people while plunging the impoverished country into a humanitarian crisis.
Washington has been actively supporting the Saudi-led war, supplying weapons and intelligence to the aggressors under the guise of fighting terror.