The Manas base in Kyrgyzstan is vital for US troops in Afghanistan
By Nick Childs
BBC World Affairs Correspondent
Reports of violence in the capital of Kyrgyzstan have prompted the US embassy there to express deep concern, and the Russian government to call for restraint.
These reactions help underline the strategic significance of Kyrgyzstan and the region it occupies.
has found itself in the cockpit of what has been dubbed the new "great game" in the region - so-called because the modern big powers jostling for influence there appear reminiscent of the 19th Century contest between the British and Russian empires over access to India.
It has been a scramble for access to energy and other natural resources, trade routes, and more recently Western supply routes for operations in Afghanistan.
Gunfire has broken out in the Kyrgyzstan capital Bishkek
For Kyrgyzstan - one of the poorest of the neighbours in this region - the chief international focus has been access for military bases.
Manas air base
has become a key strategic staging post for the US military in Afghanistan - especially after the closure of the so-called
K2 base in Uzbekistan
That itself followed the souring of relations between the US and Uzbek governments in 2005, after the Uzbek authorities cracked down violently on an internal threat posed by Islamic militants.
But the sensitivities have been growing - not least from Moscow, as the US-led operations in Afghanistan, and therefore also Washington's military interest in the region, have become ever more prolonged.
The Kyrgyz authorities have played Washington off against Moscow.
President Kurmanbek Bakiyev
had already been pressing Washington for significant increases in the rental payments for Manas.
But in early 2009, on the back of a Russian promise of a huge aid package, he announced that the base would close.
President Bakiyev asked for rent increases for the Manas base
It took a personal intervention by President Barack Obama to keep the Manas base open to the Americans. Even then it was on a compromise basis, under which Manas was to be described as a "transit centre".
But the bumpy nature of relationships in the region has helped fuel a debate over how much commitment the West - and especially the US - should have in the region in the long term, particularly if operations in Afghanistan eventually tail off.
There are broader Western concerns about stability, governance, access to energy, and worries about the spread of Islamic militancy there.
But how these should be translated into long-term policy, against the background of Russian, Chinese and other local sensitivities, is very much open to question.