MILAN-- Eni SpA reported a wider net loss in the fourth quarter as the sharp drop in crude oil prices played havoc with the Italian oil and gas group's performance, knocking revenue lower and triggering hefty write-downs.

Eni said on Wednesday that its net loss widened to EUR2.34 billion in the three months to end-December, compared with a net loss of EUR647 million in same period last year, on a 10% drop in revenue to EUR26.83 billion.

Adjusted profit, which strips out special items, dropped by two-thirds to EUR464 million euros, below a consensus analysts' forecast EUR614 million.

Showing similar strain to its bigger European rivals like Royal Dutch Shell NV, BP PLC, and Total SA, Eni said it marked down the value of its oil and product inventories by EUR860 million and booked asset impairments and other after-tax charges of EUR1.94 billion.

However, Eni said on Wednesday that it has declared a slightly higher yearly dividend of EUR1.12 a share, up from EUR1.10 a share in 2013.

Production in the fourth quarter rose 4.5% to 1.65 million barrels of oil and equivalent natural gas volumes a day. Eni said it expects production to increase this year as new projects come online in Angola, Congo, the U.K., the U.S. and Norway.

For the full year, Eni said net profit fell by 74% to EUR1.33 billion from EUR5.16 billion in 2013.

Write to Eric Sylvers at eric.sylvers@wsj.com

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