UPDATE 1-Megafon keeps targets after profit miss on depreciation, weak rouble

* Q1 net profit falls 43 pct to 7.2 bln (poll: 10 bln)

* Bottom line eroded by Scartel D&A costs, weaker rouble

* Core profit margin, sales growth targets ahead of competitors

(Adds details, competitors)

MOSCOW, May 29 (Reuters) - Russian mobile phone operator Megafon said depreciation costs related to last year's acquisition of Scartel and a weaker rouble weighed on its earnings in the first quarter but its core profitability and sales growth targets were intact.

Telecoms operators have so far proved resilient to Russia's economic downturn, with consumers maintaining spending but the weakening of the local currency results in the revaluation of foreign-currency liabilities, translating into non-cash losses.

Megafon, the last of the "Big Three" mobile operators to report first quarter results, said on Thursday it still expected to grow revenues by 6-8 percent this year and achieve a core profit margin of at least 44 percent despite the weaker economy.

Rival MTS expects 3-5 percent sales growth this year while Vimpelcom has recently cut forecasts and now expects "low to mid single digit" declines in revenue.

Megafon, Russia's second-largest mobile operator behind MTS, bought high-speed wireless Internet provider Scartel last year in a deal that gave Megafon a lead in 4G infrastructure and helped it increase its customer base and revenue but hurt profitability.

Its first-quarter net profit fell 43 percent to 7.2 billion roubles ($208 million), down from 12.6 billion roubles in the same period of 2013, it said in a statement, while analysts had forecast 10 billion roubles.

The results were eroded by around 14 billion roubles in depreciation and amortization costs, mostly related to the Scartel network, and a foreign exchange loss of around 5 billion roubles due to the revaluation of its foreign currency debt.

But Megafon, which is controlled by Russia's richest man Alisher Usmanov, reported a forecast-beating operating income before depreciation and amortization (OIBDA) which edged up 0.4 percent to 32.5 billion roubles against the Reuters poll forecast of 32.3 billion.

Revenues grew 10.6 percent to 74.9 billion roubles, slightly above the 74.8 billion rouble estimate, driven by an increase in subscriber base and booming data services which helped offset a 1.5 percent decrease in voice revenues. ($1 = 34.5882 Russian Roubles)

(Reporting by Maria Kiselyova; Editing by Megan Davies and Elizabeth Piper)