Japanese Prime Minister Junichiro Koizumi is winding up his visit to Central Asia after talks with the Kazakh and Uzbek leaders.
Japan wants to improve ties with Central Asia
The visit, the first by a sitting Japanese premier to the region, has focused primarily on energy deals.
In Kazakhstan, Mr Koizumi signed a deal on joint development of uranium, which Japan needs for nuclear energy.
Analysts say Mr Koizumi's trip is in part to counter growing Chinese and Russian influence in the region.
It is also about energy, with Tokyo keen to reduce its reliance on imported oil and gas from the Middle East.
Mr Koizumi held talks with Uzbek President Islam Karimov on energy and uranium deals, and afterwards stressed his commitment to the region.
"I hope my visit underlines Japan's intention to have closer ties with Uzbekistan and shows Japan has much interest in Central Asia and intends to work more actively here," he said.
No agreements were signed, but Mr Karimov said he expected co-operation between the two sides to increase.
"We see a huge potential in our ties, we are ready to offer our resources and supply uranium to Japan," he said.
Mr Koizumi now travels to the Uzbek city of Samarkand before returning to Tokyo.
The issue of human rights was also touched on during talks with the Uzbek leader, Japanese officials said.
Mr Karimov has been shunned by the United States and the European Union since the crackdown in Andijan in May 2005.
Uzbek officials say 187 people died when troops fired on a group of Islamic extremists, but witnesses says soldiers killed anti-government protesters and put the figure much higher.
"The word Andijan was not mentioned but the prime minister made himself very clear on this," an unidentified Japanese official told Reuters news agency.