Sales of the Lumia phones in the second quarter increased by 32 percent compared with the first three months of the year to 7.4 million handsets but this was still at the lower end of analysts' expectations.
The company's total handset sales, which include the no-thrills "feature" phones popular in developing markets, were down 27 percent on the same quarter last year at 61.1 million units.
Greger Johansson, an analyst with research firm Redeye in Stockholm, said he was worried about the rapid sales decline of the feature phones, adding that the company has to keep launching new Lumia models at a rapid pace to keep up client interest in the Windows phones.
Nokia "has a few more quarters to make it. They are now more or less breaking even, that's a good starting point," he said.
"The company has to keep on releasing new, very attractive products to catch market share from Samsung and Apple. I think Nokia still does have pretty good chance of doing that."
Nokia said its devices and services sales in the world's largest devices market, China, fell by 57 percent to 232 million euros while sales in North America the frontline of the smartphone market dropped by 4 percent to 123 million euros.
Still, Nokia CEO Stephen Elop said the mobile phones business unit started to demonstrate "some signs of recovery in the latter part of the second quarter following a difficult start to the year."
He said the Lumia 520 has "enjoyed a strong start in markets like China, France, India, Thailand, the UK, the US and Vietnam."
Sales by the company's network division, Nokia Siemens Networks, fell by 17 percent to 2.8 billion euros.
Nokia earlier this month announced its intention to purchase Siemens' half of the 2007 joint venture, in a move to help bolster its struggling smartphone division. On Thursday it said it expects to cut the annual operating costs in Nokia Siemens by 1.5 billion euros at the end of 2013, compared with the end of 2011. It had previously forecast to cut costs by 1 billion euros.
Elop said Nokia Siemens Networks "continued to deliver well against its focused strategy," adding he looks forward to strengthening the division as "a more independent entity."