UPDATE 1-CSN cash crunch eases as it refinances 2016, 2017 bank debt

RIO DE JANEIRO/SAO PAULO, Sept 3 (Reuters) - Brazilian steelmaker Cia Siderurgica Nacional said on Thursday it extended repayment of 2.57 billion reais ($687 million) of loans as it rushes to ease looming debt payments amid a decline in steel prices and demand and a weakening of Brazil's currency.