Former chief executive Jorma Ollila suggests he will leave by 2012 amid management changes at top of mobile phone giant

The turmoil at the top of Nokia has continued for a third day, with the company saying on Tuesday that its chairman and former chief executive Jorma Ollila is to step down - though not until 2012.

The Finnish company, the biggest seller of mobile phones in the world, ejected its chief executive Olli-Pekka Kallasvuo on Friday, and then lost its head of mobile, Anssi Vanjoki, on Monday when he resigned, apparently disappointed at the appointment of Stephen Elop, formerly at Microsoft, to the role of chief executive.

A Nokia spokeswoman said that while no definitive announcement had been made about Ollila's post, he has said he would be "at the disposal of the company" until the annual general meeting of the company in spring 2012.

Last Friday Ollila said the board had asked him to stay on as chairman for a transitionary period. "The board did want me to continue because this is a particularly difficult time. My time will be up soonest," he said then, but added, "no time set."

Nokia's announcement on Friday came after its stock had continued its plunge: it is down more than 20% this year following two profit warnings, while the company's management had come under increasing pressure.

On Tuesday, the company presented new telephones and applications for its handsets, hoping to get back into the high-end smart phone race.

"Today our fight back to smart phone leadership shifts into high gear," said Niklas Savander, executive vice president of Nokia's markets unit said at the Nokia World event in London. "Despite new competition, Symbian remains the most widely used smart phone platform in the world."

The company unveiled three new smart phones the C6, C7 and E7 with price tags ranging from 260 to 495.

But markets were not impressed, and Nokia stock closed down more than 3% in Helsinki at 7.64 ($9.82).

Vanjoki is a board member, and in charge of the top-end mobile smartphones, an area Nokia is keen on improving as it tries to rival Apple's iPhone and Research In Motion Ltd.'s BlackBerrys, and phones built around Google Inc.'s Android software.

Vanjoki will remain for a six-month notice period, Nokia said. Vanjoki, who joined Nokia 20 years ago and has been a board member since 1998, said on Monday he felt "the time has come to seek new opportunities in my life."

He had previously been seen as a potential successor to outgoing Kallasvuo but drifted away from the top management when the company reshuffled responsibilities earlier this year and Mary McDowell was appointed top chief of the mobile phones business.

During Kallasvuo's leadership investors had long been expecting something fresh and new from the company that once had the innovative edge in the industry, but that has not happened. He has also been unable to tackle problems in the North American market, the company's worst performer, despite a pledge to make it a top priority.

Markets have also not been impressed by Symbian, which is older than Apple's software and wasn't designed from the ground up for touchscreen phones. Other manufacturers that had used Symbian have mainly jumped ship to Android.

• This article was amended on 16 September 2010. The original referred to the chairman of Nokia as Jorma Ollia. This has been corrected.