Following the collapse of the USSR in 1991 Armenia gained independence and inherited its section of the Turkey-USSR border. Though Turkey recognised Armenian independence, relations between the two countries almost immediately soured and the border was shut: Turkey opposed irredentist claims to eastern Turkey by Armenian nationalists championing a 'United Armenia', as well as Armenia's efforts to achieve international recognition of the Armenian Genocide; Turkey also supported its close ally Azerbaijan in the war over Nagorno Karabakh.[24] Relations thawed slightly in the 2000s decade, resulting in the signing of the Zurich Protocols in 2009, in which it was envisaged the border could re-open.[25] The talks foundered however and the border remains closed.[26][27]