Kuwait has said it will not allow the United States to use its territory for any strike against Iran.
"The president will make very clear that the United States takes very seriously its commitments to our allies in this region," Rice said aboard Air Force One on the way to Kuwait.
NO "BLINDING FLASH"
Bush left the Holy Land after painting an upbeat picture of talks this week with Israeli Prime Minister Ehud Olmert and Palestinian President Mahmoud Abbas intended to build on a U.S.-hosted peace conference at Annapolis in November.
Challenging sceptics, Bush said on Thursday there would be a signed peace treaty before he left office in January 2009.
While Abbas and Olmert praised Bush's peace bid, neither offered significant concessions to the U.S. leader, who until recently had mostly shunned hands-on Middle East diplomacy.
Bush said he would urge Arab allies to "begin to reach out" to Israel to nurture the peace process. After Kuwait he will visit Bahrain, the United Arab Emirates, Saudi Arabia and Egypt.
"There isn't going to be a blinding flash in any of this, not on this trip, not on the next trip, but this is a process of moving forward," Rice said. "You will see that as the bilateral process continues to move forward the Arabs will do more."
Bush's hopes of rallying Arab opposition to Iran were underscored by a confrontation between U.S. and Iranian vessels in the Strait of Hormuz last weekend. He warned Iran of "serious consequences" if it happened again.
But his task will be made harder by a U.S. intelligence report that concluded Iran had stopped its nuclear arms programme in 2003, contradicting Bush's earlier assertions Tehran was actively pursuing a bomb.
