HELSINKI - Finland's telecoms giant Nokia reported Thursday that it remained deep in the red at the start of the year, with sales in its main business, networks, on the decline.

The company posted a loss of 488 million euros ($532 million) in the first quarter, an improvement from the 609 million euros a year earlier, prompting chief executive Rajeev Suri to say he believed in an "improving business momentum, even if some challenges remain".

But while the company's overall sales declined by two percent to 5.38billion euros, sales in its core networks business fell by six percent, to 4.9 billion euros.

"We saw encouraging signs of stablisation in mobile networks," Suri told reporters in a conference call.

The company is eyeing business opportunities offered by the "path to 5G roadmap", Suri said, referring to the worldwide roll-out of the lightening-fast 5G mobile internet service that operators expect to begin by 2020.

Once the world's number one handset maker, Nokia transformed itself into a network equipment company and bought its hugely unprofitable French-American rival Alcatel-Lucent a year ago, resulting in the whole group's results to plunge into the red in 2016.-AFP