* Fortum to reduce thermal exposure in Russia

* Q4 operating profit 1.07 bln euros

* Fortum shares down 7%, Uniper down 18.8%

HELSINKI, March 3 (Reuters) - Fortum will not make new investments in Russia and will reduce its exposure to thermal power production there following Moscow's invasion of Ukraine, as the Finnish utility grapples with a crisis in one of its major markets.

Fortum's Russian division operates seven thermal power plants for district heating in Russia, while Germany's Uniper , in which Fortum owns 78%, has five power plants across the country through its Unipro subsidiary.

The fallout from the war in Ukraine has dealt an extra blow to Uniper because it was also one of the backer's of Russia's Nord Stream 2 gas pipeline, which Germany has put in ice following Moscow's full-scale invasion of its neighbour.

Fortum said on Thursday - like Uniper a day earlier - that it would continue to run its Russian business.

But Chief Executive Markus Rauramo added: "Business as usual cannot continue. For now, we have stopped all new investment projects in Russia until further notice and we will continue to reduce our thermal exposure in Russia."

He declined to say how Fortum would reduce this exposure. In recent years it has sold two thermal power plants in Russia, while Uniper has divested a gas field stake.

Fortum's Russian operations accounted for about 20% of the group's comparable operating profit last year, while roughly half of Uniper's long-term gas contracts are sourced from Russia.

Fortum's shares fell as much as 7% on Thursday, while shares in Uniper, which is one of five co-funders of the Nord Stream 2 gas pipeline and has a 1 billion euro ($1.1 billion) exposure to the project, were down as much as 18.8%.

In a strategy update, Fortum, which also reported quarterly results, said it would scrap plans to sell off its consumer electricity business and its Polish district heating business.

In Finland, the company plans to apply for a licence to continue operating two nuclear units at its Loviisa plant until the end of 2050, it said.

Fortum posted a fourth-quarter comparable operating profit of 1.07 billion euros, up from 928 million euros a year earlier and beating the 983.5 million euros expected by analysts in a poll provided by the company.

($1 = 0.9019 euros)

(Reporting by Anne Kauranen and Christoph Steitz Editing by David Goodman and Mark Potter)