Their current importance is due both to their geostrategic value, located between three great powers- Russia, China and India - and in their energy potential, with reserves to all forms of energy, including renewables. For Spanish foreign policy, there are two particular areas of interest in these countries. Firstly, in terms of security, some offer logistical support to the Spanish contingent of the ISAF based in Afghanistan and they remain important countries for the promotion of peace and stability there. Secondly, in economic terms, there are several Spanish companies in Kazakhstan and Uzbekistan.

With a total surface area of more than 4 million square kilometres, greater than that of India, but with barely 60 million inhabitants, post-Soviet Central Asia is increasingly attracting attention, not only for its vast natural resources but also its strategic location. Situated between the Caspian Sea, south-eastern Russia and northern China, these five countries, of diverse size, population and socio-economic status, seek consolidation through alliances with their two great neighbours, and also through agreements with the European Union and the United States while also maintaining their historic and cultural links with Turkey and Iran.

The region's proximity to Afghanistan, with which Turkmenistan, Tajikistan and Uzbekistan share a border, makes it a key area not only in the fight against Afghan Islamist extremism but also against drug trafficking from the country which, according to data from the UN, produces close to 90 percent of the world's opium.

Kazakhstan, the largest of the five countries, has extensive hydrocarbon and uranium reserves and, since January 2015, has been a member state of the Eurasian Economic Union, with Russia, Belarus, Armenia and Kyrgyzstan, maintaining strong economic and commercial links with the European Union, Turkey and other countries in the region and has not ruled out its participation in projects for the transportation of natural gas to Europe through the Caspian Sea. It is a member of the Shanghai Cooperation Organisation along with China and Russia and other central Asian former Soviet republics: Tajikistan Uzbekistan and Kyrgyzstan. These three countries are also members of the Collective Security Treaty Organization, a political and military alliance led by Russia and which includes Armenia and Belarus.

Uzbekistan, with almost 30 million inhabitants, the most populated country in the region was also a member of the CSTO but suspended its participation in June 2013 when Tashkent opposed to the strengthening of the military component of the alliance. In its relations with Afghanistan, Uzbekistan has preferred to maintain bilateral ties. Uzbekistan entered a new political phase after the death of President Karimov in September 2016. His successor, President Mirziyoyev, has adopted a major programme of reforms and modernisation of the country since his election in December 2016.

Unlike other Central Asian republics whose strongly presidential regimes have their roots in their Soviet past, Kyrgyzstan has undergone a profound and at times turbulent process of change, culminating in the constitutional reform that turned it into a parliamentary republic in 2010, the only one in post-Soviet central Asia. Its economy is one of the weakest in the region along with Tajikistan, with both critically dependent on remittances from the many emigrants living abroad, particularly in the Russian Federation. Kyrgyzstan is also home to a Russian air base.

In the 1990s Tajikistan was the scene of a cruel civil war between communists and the Islamic opposition, which ended in 1997 with a national reconciliation agreement and the inclusion of opponents in the Government structures. However, in 2015, the Tajik President decided to illegalise the opposition Islamic Renaissance Party, strengthening his power as President of the Republic. With 1,300 kilometres of border with Afghanistan, Tajikistan, where Russia has an important military base, is considered crucial in the prevention of drugs trafficking from Afghan territory to Europe through post-Soviet space.

Turkmenistan, the least populated country in central Asia and second in terms of size, has the fourth largest natural gas reserves in the world, the pillar of its economy. Since its independence from the Soviet Union it has maintained a policy of neutrality and has developed an almost autarchic form of isolationism. Although formally a member of the post-Soviet Community of Independent States, Turkmenistan has practically remained on the sidelines of the integrationist processes of this format. Its economy is subject to the growing influence of China, the primary destination for its gas exports.