Awwal 17, 1432 H / April 21, 2011, SPA -- Nokia, the world's largest mobile phone maker, Thursday reported a rise in its first quarter net profit and said it had signed a cooperation agreement with software giant Microsoft, according to dpa. Nokia's net profit of 231 million euros (337 million dollars) compared with the 175 million euros it reported in the same business period in 2010. The result was better than analysts had forecast, prompting the share price to gain 3 per cent. The planned cooperation with Microsoft - announced in February - would include using Microsoft software for Nokia's high-end mobile telephones and phasing out Nokia's own Symbian operating system, which has seen its market share slide. Nokia estimated its share of the smartphone market dropped to 26 per cent in the quarter, compared to 31 per cent in the preceding quarter. Of the overall global handset market, Nokia estimated it had a 29 per cent share, down from the 33 per cent it had a year ago. First quarter net sales increased 9 per cent year-on-year to 10.4 billion euros, the Finnish company said. Nokia has faced increasing competition, especially in the smartphone sector, from the likes of Apple, which produces the iPhone. Chief executive Stephen Elsop said in a statement Nokia expected "a more challenging second quarter." The Finnish group sold 108.5 million handsets during the quarter, up 1 per cent year-on-year and down 12 per cent compared with the fourth quarter of 2010. The tally included 24.2 million smartphones. The average sale price of Nokia handsets in the quarter was 65 euros, down from 69 euros in the preceding quarter.