Nokia aims to tackle increasing competition in the smartphone market by halving its portfolio next year, its smartphone unit executives said.

The Finnish firm continues to sell more smartphones than any of its rivals, but has lost ground to the likes of Apple and Blackberry-maker RIM.

We see ... really fierce competition certainly in the high-end, but we also see it in the mid to low end of smartphones increasing, Jo Harlow, the new chief of Nokia's smartphone unit, said in a webcast published on Thursday.

We will defend our position, but we believe we also have tools to play offence as well as defense, said Harlow, former captain of Duke University's women's basketball team.

Harlow was appointed head of the new unit in October, after the firm reported a sharp fall in smartphone market share.

Nokia, which introduced around 20 smartphone models in 2009, said it had cut its smartphone portfolio for next year roughly in half.

We have cut down unnecessary differentiation, so that we have a far more focused portfolio for next year. We can put more effort behind these products, said Antti Vasara, head of smartphone unit R&D.

(Reporting by Tarmo Virki, editing by Will Waterman)