Turkmenistan's declaration of "permanent neutrality" was formally recognized by the United Nations in 1995. Former President Niyazov stated that the neutrality would prevent Turkmenistan from participating in multi-national defense organizations, but allows military assistance. Its neutral foreign policy has an important place in the country's constitution. Although the Government of Turkmenistan claims to favour trade with and export to the United States, and Turkey, its single largest commercial partner is China, which buys the vast bulk of Turkmen natural gas via the Central Asia–China gas pipeline. Turkmenistan has significant commercial relationships with Russia and Iran and growing cross-border trade with Afghanistan. The Government of Turkmenistan often appears to use the conflicting interests of these regional powers as a means to extract concessions, especially on energy issues.