Sales of mobile handsets in Russia are estimated to have risen by 25 percent in units last year, but the market value lagged as the average selling price declined, Russia's top mobile operator MTS said.

Mobile handset sales rose to 34.8 million units in 2010, MTS said in a Thursday statement summing up the results of market research from its retail unit.

In monetary terms, sales increased 7 percent to 155.2 billion rubles ($5.2 billion), as the average selling price declined 14 percent.

The company also said fourth-quarter sales grew 18 percent year-on-year to 10.4 million units and were up 16 percent in monetary terms.

MTS, which had a 13.6 percent share of the Russian mobile phone market last year, also said sales of smartphones in its retail chain more than doubled in the final quarter of 2010 compared with the third quarter due to increased demand ahead of New Year.

It gave no breakdown for overall Russian sales by vendors.

(Reporting by Maria Kiselyova; Editing by David Holmes)

($1=30.14 Rouble)