The world's top cellphone maker Nokia will unveil its first touch-screen phone at a media and analyst event in London next week, two industry sources.

Smaller handset vendors - LG Electronics, Apple and Samsung Electronics - have rolled out numerous popular touch-screen phones over the last two years. Both sources said Nokia was set to unveil the phone, codenamed "Tube", on October 2.

"The phone is extremely important. We have been waiting for the market leader to respond to iPhone for a year and a half now. There is a lot of pressure on Nokia," said Carolina Milanesi, analyst at Gartner.

Nokia said in July it would introduce its first touch-screen phone this year, and would sell it more cheaply than rival touch-screen models in order to tap into a higher-volume market.

"The demand outlook in emerging markets, like India, is good for a cheaper touch-screen phone," said Hannu Rauhala, an analyst with Pohjola Bank.

Kai Oistamo, head of Nokia's devices business, said in July the Finnish firm was fully committed to bringing a complete portfolio of touch devices to the market, both in the high-end and low-end segments.