Middle class but disillusioned, Igor and Rina are typical of the new generation of Russian activists who cannot wait to join a protest on Saturday against strongman Prime Minister Vladimir Putin.

Like others from a host of members of Russia's middle class -- young, Internet-savvy, urban -- Igor, 34, a small business co-owner, and Rina, 19, a journalism student, are ready to rally for hours despite sub-zero temperatures.

"I am not indifferent about my country's destiny," said Rina, denouncing widespread corruption in Russia, state-controlled media and alleged fraud during December 4's parliamentary elections.

"If there are a million people in the Moscow streets, then things will start to change" in Russia, added Igor.

Won by the ruling United Russia party, the parliamentary elections were criticised by the opposition and international observers as fraudulent and sparked a protest movement unprecedented since Putin's rise to power.

Putin's decision to seek a third term as head of state in presidential elections on March 4 -- after having served two terms in 2000-2008 -- only added to protest sentiment already fuelled by what critics say is endemic corruption and a totalitarian political system.

Tens of thousands of Russians took to the streets in Moscow and other cities on December 10 and 24 to demand a repeat parliamentary vote and a "Russia without Putin." Another demonstration is planned for Saturday one month ahead of the presidential polls.

Organised through social networks, the protesters are chiefly young middle class people who profited from years of economic stability under Putin's presidency.

The Russian media dubs them "office plankton" -- people who until recently have been active in relatively modest professional jobs, but quite inert when it came to civil society activities.

But now they have risen to the surface and are challenging the authorities as foreign travel gives them a wider perspective and the Internet allows them to discover and even expose the extent of abuses by officials.

"I want people to stop being afraid to go to rallies ... I want this to become a necessity for everyone," said Rina, who calls herself an "active citizen."

Igor, a co-owner of a small technology company of 30 employees, participated for the first time in his life in a rally on December 10 at Moscow's Bolotnaya Square.

"I felt great pride, a sense of unity never felt before," he said with a smile.

Apart from the alleged electoral fraud, Igor's political awakening was sparked by Putin's announced return to the Kremlin in the March 4 elections, which theoretically allows him to stay in power for another 12 years.

"In 12 years, it will be the end of our country. I will be 46. That means that I will spend the most active part of my life in a totalitarian state. I do not want that. I am ready to act against it," he said.

But analysts say that the middle-class orientation of the protest movement is a possible weakness as it has yet to attract the mass support of lower income groups, many of whom still trust Putin to ensure stability.

A survey by the independent Levada Centre at the last protest on December 24 showed that 62 percent of protestors had a higher education and only four percent described themselves as workers.

In a bid to show Putin still retains wide backing in some sections of society, a series of mass rallies in his support are being held over the next weeks with one on Saturday in Moscow aiming to rival the opposition protest.