Rice's visit closely follows a visit by U.S. Assistant Secretary of State Daniel Fried. It comes as votes are still being counted for the Afghan parliamentary elections and preparations are under way for Kazakhstan's December presidential polls.
State Department spokesman Sean McCormack said the talks would focus on economic development, security issues, and democracy building.
"[The] general message is one of support for the ongoing political change and economic reform that is ongoing in this important region and to underline our support for those who will undertake the necessary political and economic reforms, to have respect for human rights, to promote free speech, to promote good governance," McCormack said.
McCormack, in response to repeated questions, said the trip was not an effort to counter Russian and Chinese influence but to affirm Washington's support for reforms.
But he indicated Rice will seek to reaffirm support for the ongoing efforts in Afghanistan to stabilize the government and defeat Taliban and Al-Qaeda forces.
In July, Kazakhstan, Kyrgyzstan, and Tajikistan joined China and Russia via the Shanghai Cooperation Organization in calling for the United States to set a timetable for closing all its bases in Central Asia. They said the bases are no longer needed because the U.S. combat operations against the Taliban in Afghanistan are winding down.
But McCormack challenged this.
"One important voice that was not heard from with respect to this communique was Afghanistan. They weren't participants in that conference or that communique," McCormack said. "And we -- I think subsequently, the Afghan government has said that it is important to have a continued -- continued assistance from the outside world as it moves down the pathway to consolidating its gains in -- security gains, as well as its gains in promoting democracy."
The United States uses an air base in Kyrgyzstan to support its efforts in Afghanistan but will vacate an Uzbek base within months at Tashkent's request.
Unlike Fried, Rice will not visit Uzbekistan, which has distanced itself increasingly from the United States following the events in Andijon in May.
Fried reiterated U.S. calls for an independent international investigation into the Andijon crackdown but McCormack said there has been no change in Tashkent's position.
"There are real concerns about some of the recent actions by the Uzbek government," McCormack said. "And I think that at this point, given Dan Fried's recent visit to Uzbekistan, that Uzbekistan -- the Uzbek government should reflect upon what sort of relationship it would want with the United -- not only the United States, but the rest of the world. And I think that there -- you know, we will -- we will see over time what kind of relationship the Uzbek government wants with the rest of the world. We stand ready to have a different kind of relationship."
McCormack said Rice might travel to other countries during her regional tour, but he declined to elaborate.
(RFE/RL's Nathaniel Szep contributed to this report.)
Central Asia: Q&A With U.S. Assistant Secretary Of State Daniel Fried