By Sarah Shenker
In a lavish ceremony in the Kremlin earlier this month, Uzbekistan and Russia signed a mutual defence pact.
Uzbek President Karimov, left, has turned towards Russia
"By signing this treaty... we showed once again with whom we will build our future," Uzbek President Islam Karimov said afterwards. "Russia is our most reliable partner and ally."
It marked a stark contrast to a few years ago, when the US appeared to be Uzbekistan's favoured foreign friend, and relations with Russia, its former ruler, were cooler.
Mr Karimov's about-turn highlights how US and Russian influence in the Central Asian states - Uzbekistan, Kazakhstan, Kyrgyzstan, Tajikistan and Turkmenistan - has been shifting.
And with China's emergence as a major power, the region's politics and security concerns are set to become more complex.
The US presence in the region dates back to the beginning of the "war on terror", when the US needed staging points in the region for operations in Afghanistan.
Uzbekistan and Kyrgyzstan both provided air bases. But as well as these operational concerns, the US has also sought to monitor security in the region itself.
US: One in Kyrgyzstan, base in Uzbekistan to be closed
Russia: One in Kyrgyzstan, one in Tajikistan. Has conducted join military exercises with all Central Asian states except Turkmenistan
China: No bases. Has conducted military exercises with Russia
"There is concern about political stability in Central Asia, and about terrorists and drugs coming in from Afghanistan," according to Kyrgyzstan-based analyst Michael Hall, of the think tank International Crisis Group.
Ensuring stability is important to Russia, too, according to Oksana Antonenko, a senior fellow at the International Institute of Strategic Studies.
"Russia wants to deal with these threats on the ground in Central Asia, rather than wait for them to move onto Russian territory," she said.
China is also watchful - its western province of Xinjiang, which is home to Muslim Uighurs, some of whom want an independent homeland, borders on Tajikistan and Kyrgyzstan.
All three worry about the potential for instability in Kyrgyzstan, which saw a peaceful revolution earlier this year, and Uzbekistan, whose suppression of an uprising in Andijan in May led to the loss of hundreds of lives.
The US sees its military bases in the region as counterweights to Russian - and Chinese - influence.
But in the wake of the Andijan killings, the US moved to distance itself from the Uzbek government, which responded by telling the US to leave its airbase.
Uzbekistan has now asked European troops within Nato to leave its territory, too.
Uzbek relations with the US took a turn for the worse after Andijan
There is also a perception, Ms Antonenko said, that the US was involved in the peaceful "tulip revolution" in Kyrgyzstan which ousted President Askar Akayev, and it is now regarded with suspicion by the region's other rulers.
Russia, on the other hand, has set itself up as the guarantor of safety in the region, through regional bodies such as the Shanghai Cooperation Organisation and the Collective Security Treaty Organisation.
It openly supported Uzbek President Islam Karimov after the events at Andijan.
The region is important for Russia, says Ms Antonenko, because it is one of the few left when Russia can maintain its status of a great power that it has lost elsewhere.
However, its ability to carry through its commitments, such as the new mutual defence pact, is doubtful, Ms Antonenko said.
"It's important for it to seem like a military power, but Russia's ability to project power is very limited," she said.
"It is not really involved in operations there and it doesn't want to divert resources from the Caucasus. It's a symbolic presence."
The most likely source of competition between the rival powers is over natural resources.
Kazakhstan has enormous oil reserves, estimated at 26bn barrels, and Turkmenistan is rich in natural gas.
China is hungry for energy to keep its economy growing, the US is seeking to reduce its dependence on Middle Eastern oil, and Russia is keen to exploit potential transit routes for its resources through Central Asia.
WORLD OIL RESERVES
Saudi Arabia: 261.7bn barrels
Iraq: 112.5bn barrels
Russia: 69bn barrels
Kazakhstan: 26bn barrels
Azerbaijan: 589m barrels
Uzbekistan: 297m barrels
Turkmenistan: 273m barrels
Source: CIA World Factbook
Some analysts have described the interplay of US and Russia - and now Chinese - interests as a new version of the 19th Century "Great Game", which saw Russia and the British Empire compete for influence in the region.
Lutz Kleveman, author of The New Great Game: Blood and Oil in Central Asia, believes the US is using the "war on terror" to further its oil interests in the region.
Russia and China, he said, were gaining ground - Russia because it is an important regional trading partner, and China because it is becoming more powerful, in military and economic terms. China is buying up oil concessions and opening a major new pipeline to pump oil from Kazakhstan.
But others argue that Russia not only has its own, much larger oil reserves, but also that there is little evidence the region is such a priority to Moscow as, say, the Ukraine.
The US denies it is revisiting Cold War rivalries on new ground.
Earlier this year, US Assistant Secretary of State for Eurasian affairs Daniel Freid said: "We do not look at Central Asia as an object in a Great Game. We do no look at this as a zero-sum contest between us, the Russians and the Chinese."
Characterising the strategic interests at play in Central Asia as a new Great Game can also overlooks the most important players, according to Daniel Kimmage, a Central Asia analyst with Radio Free Europe/Radio Liberty, a US-government funded overseas broadcaster.
"[It] reduces everything in the region to the actions of those great powers, where in most cases local players are more important", he said.
On the ground, competition between the US, Russia and China has had a limited effect on domestic policy in the region, he said.
Uzbekistan decided on its own to kick out US and Nato troops - albeit after Russian and Chinese encouragement, he said.