Armenian independence from the Soviet Union came on September 21, 1991, when the war over Nagorno-Karabakh was in full swing. Armenia's energy supply during the Soviet Union was designed as an integrated part of the Trans-Caucasus electrical grid. After the collapse of the Soviet Union, and because of the lack of internal energy supply, Armenia faced a critical situation." Turkey and Azerbaijan closed their borders with Armenia, putting a fuel embargo on the country. Azerbaijan blocked a natural gas pipeline from Turkmenistan which was flowing through Azerbaijan, effectively cutting off about 90% of the natural gas supply of the country. During the clash, which lasted until May 1994, Azerbaijan blockaded roads, rail lines and energy supplies, leading to severe energy shortages in Armenia.