By Monica Whitlock
BBC correspondent in Tashkent
Chinese President Hu Jintao has signed a number of accords with the government of Uzbekistan on a state visit to meet President Karimov in Tashkent.
Mr Hu (L) and Mr Karimov want to strengthen relations
The agreements cover mainly oil and gas development and other Chinese investments.
China has become one of Uzbekistan's main trading partners in recent years and the rapid expansion of the Chinese economy is having a big impact throughout central Asia.
President Hu clinked a champagne toast with Mr Karimov as the two celebrated their friendship in the presidential palace in Tashkent.
It was, they said, a visit of great importance.
"Our partnership is stronger every year," said Mr Karimov, "and we're looking forward to a bright future."
The main accord is on the development of Uzbek oil and gas. No details were released, but the Uzbeks were hoping for a broad-ranging deal covering both prospecting and extraction from their undeveloped energy sector.
That is in line with China's broader strategy in central Asia.
In Kazakhstan, too, there is talk of a huge pipeline that will stretch all the way to Xinjiang in western China, where the Chinese need new sources of energy to expand industry in their poorest region.
On the streets in central Asia, you can see the impact of the new China, with almost every consumer good now imported from China.
At the palace there was a nod too to China's and Uzbekistan's security concerns.
Some of the Muslim, Turkish speaking Uighur people of Xinjiang are deeply hostile to Beijing, while some underground Uzbek groups feel the same way about Mr Karimov's administration.
Much as in Beijing before a state visit, the army has been out in Tashkent tidying up the city and lining the avenues with flags.
Police broke up a small anti-government demonstration before President Hu arrived on Monday and detained the demonstrators. Most, perhaps all, have now been released.