(ADVISORY- Reuters plans to replace intra-day European and UK stock market reports with a Live Markets blog on Eikon - see cpurl://apps.cp./cms/?pageId=livemarkets for site in development. See the bottom of the report for more details) Updates prices)
* FTSEurofirst 300 index falls 1.6 percent
* Miners and banks among top decliners
* Commerzbank sharply down after profit slump
By Atul Prakash and Danilo Masoni
LONDON/MILAN, May 3 (Reuters) - European shares fell to three-week lows on Tuesday, with Commerzbank leading decliners after a slump in profits and miners tracking lower metals prices following weak factory data from China.
Germany's Commerzbank fell 9.2 percent after posting a 52 percent drop in first-quarter net profit, hit by volatile capital markets and low interest rates.
"The numbers for the first quarter did not come in well ... However, external factors that have also hit other banks hard appear to be the main reason for that," said Landesbank Baden-Wuerttemberg analyst Ingo Frommen in a note.
Traders said media reports about Commerzbank's role in a tax-evasion scheme also weighed. Commerzbank said in a statement its internal systems made sure that all trades were consistent with German law.
Europe's biggest bank HSBC, which initially gained after it reported a smaller-than-expected fall in profit, pared some gains and was last down 1.6 percent.
The STOXX Europe banking index fell 3.9 percent, while the Basic Resources index was down 6.6 percent after prices of major industrial metals fell following data on Tuesday showing activity in China's factories shrank for the 14th straight month in April.
"I would be cautious on the mining sector because if global growth disappoints again, then commodities could also certainly be prone to disappointments," said Gerhard Schwarz, head of equity strategy at Baader Bank in Munich.
"The dollar is going softer and there are some concerns that the currency is no longer a tailwind for some companies. The results season is not bad overall so far, but I would doubt that the earnings outlook will really improve that significantly as expected. The impact from pricing power is still rather weak."
German chipmaker Infineon fell 4.4 percent after lowering its revenue and profit margin guidance for the full year saying it expected to benefit less from exchange rates.
According to StarMine data, 44 percent of European firms have announced results so far, of which 61 percent have met or beaten forecasts. But first quarter earnings are set to fall 18 percent from the corresponding period of 2015.
The pan-European FTSEurofirst 300 index was down 1.6 percent at 1,320.53 points by 1423 GMT after falling to 1,316.85, its lowest intra-day level since April 13.
Solvay rose 3.8 percent, the top gainer on the FTSEurofirst, after reporting better-than-expected first-quarter results, as cost cuts offset the slightly lower prices offered by the group to its customers.
French bank BNP Paribas outperformed the banking sector after saying net income rose 10.1 percent in the first quarter as lower provisions for bad loans helped offset a slump in its corporate and institutional business.
Today's European research round-up
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Editing by Gareth Jones