* FTSE 100 down 0.2 percent
* Vodafone weighs as Fitch, Oriel warn about cost of expanding
* Gold miners hit as investors sell out of the safe-haven metal
By Francesco Canepa
LONDON, March 18 (Reuters) - Britain's FTSE 100 fell on Tuesday, with Vodafone the biggest drag on the blue-chip index as investors worried that the mobile group's profits and balance sheet will take a hit from its expansion plan.
Gold miners also weighed on the FTSE, falling along with the price of the yellow metal, widely considered a safe-haven asset at turbulent times, as the likelihood of immediate military conflict in Crimea faded.
Shares in Vodafone fell 1 percent as Fitch Ratings said it would likely downgrade the group's rating by one notch if it acquires Spain's largest cable operator Ono without taking other measures to reduce its debt.
The acquisition of Ono, announced on Monday, is Vodafone's third buyout of a European fixed-broadband asset in two years and is part of its push to offer fixed-line and mobile services, pay TV and broadband.
Oriel Securities downgraded Vodafone's stock to "reduce" from "hold" following the deal, arguing that the cash the group would fork out to expand its bundled offering would hurt its profitability and increase its net debt.
"In order to defend its mobile business Vodafone has to keep buying fixed-line assets at very high multiples," Oriel's analyst John Karidis said.
"Vodafone's balance sheet is not stressed by any stretch of the imagination but...I fully expect the net debt to keep increasing."
Vodafone's shares have fallen around 11 percent from a 13-year high hit in February.
The stock knocked 2 points off the FTSE 100, which was down 12.55 points, or 0.2 percent at 6,555.43 points at 0908 GMT.
Gold miners Fresnillo, was the top FTSE faller, down 4.9 percent as U.S. gold futures slipped about 1 percent, hovering below a six-month high hit in the previous session. Randgold fell 1.7 percent.
Traders said investors were offloading their positions in the yellow metal and its miners as the threat of war in Ukraine was seen as easing. But they cautioned that any fresh sign of tensions between Russia and the West on Crimea could refuel a rise in gold.
Market participants turned their attention to the Federal Reserve's two-day meeting, where the central bank is expected to vote to reduce its monthly asset purchases by another $10 billion and could also alter its forward guidance in its statement. The meeting starts on Tuesday.
The FTSE got some support from Chilean copper miner Antofagasta, which unveiled a better-than-expected dividend for 2013, sending its stock up 3.1 percent.