NEW : However , it ca n't guarantee natural gas transit to Europe . Fight to continue over debts owed to Russia by Ukraine . It controls 20 percent of the world 's natural gas reserves and operates the world 's largest gas distribution network covering an area from Europe to the Far East , according to its website . The process will be ` ` gradual '' Gazprom operates the world 's largest natural gas distribution network .
NEW : However , it ca n't guarantee natural gas transit to Europe . Fight to continue over debts owed to Russia by Ukraine . The process will be ` ` gradual '' Gazprom operates the world 's largest natural gas distribution network .