(Telecompaper) Japanese communications provider SoftBank has agreed to raise its offer for US operator Sprint Nextel. In an attempt to fend off a rival offer from Dish Network, Softbank has increased its offer by USD 1.5 billion to USD 21.6 billion, which is still lower than Dish' offer of USD 25.5 billion. Softbank and Sprint said in a joint statement that Sprint's directors have unanimously determined that the proposal submitted by Dish is not reasonably likely to lead to a superior offer. Sprint shareholders were scheduled to vote on the offer on 12 June, but this has now been rescheduled to 25 June.