Nokia Chief Executive Stephen Elop promised to unveil a new smartphone using Microsoft's latest Windows 8 software soon, boosting expectations it will be launched before rival Apple promotes its new iPhone.

The Finnish company, which is fighting for survival after losing out to rivals in the lucrative smartphone business, is due to hold a trade show in Helsinki on September 5-6, just before an Apple event on September 12 where the U.S. competitor could announce a redesigned iPhone.

Nokia has not commented on what it will announce at the Nokia World event, but many investors anticipate a new handset designed to challenge the popularity of the iPhone and Samsung's Galaxy smartphone.

Elop did not deny a September launch but would only say Windows 8 smartphones would be released "relatively near term."

Nokia shares, which have been trading near all-time lows, rose sharply after Elop's comments. Even after Standard & Poor's downgraded the shares to deeper junk status later in the day, rating them BB- with a negative outlook, they were still up 5.6 percent at 2.12 euros around 08.07 a.m. EDT.

Elop, who was brought in from Microsoft in September, 2010, to lead Nokia's fightback against Apple and Samsung, said he was sticking to his strategy of using Microsoft software despite the limited success of Windows Phones so far.

Nokia decided in early 2011 to ditch its home-grown Symbian software for a deal with Microsoft.

"I don't think about rewinding the clock and thinking about competing elsewhere," he told reporters.

"In today's war ... (between) Android, Apple and Windows, we are very clear, we are fighting that with the Windows phone," said Elop, who was in Oslo for a meeting with Telenor chief executive Jon Fredrik Baksaas.

Nokia lost 1.53 billion euros in the second quarter and sold just 4 million Windows phones in the period, well short of Apple's sales of 26 million iPhones and Samsung's 50 million smartphones.

Nokia shrugged off S&P's announcement, saying it had sufficient liquidity and was saving money. S&P cut Nokia's rating in April to BB+ - junk status - meaning conservative investors like pension funds will consider it too risky to hold.