Britain's FTSE stalls after touching 15-year peak

* FTSE 100 edges lower after posting a new high

* New (KOSDAQ: 160550.KQ - news) index peak just 0.4 pct off December 1999 record

* Coca-Cola HBC fall away on Russia tensions

* Greek deal hopes underpin financials (Adds detail, updates prices)

By Alistair Smout

LONDON, Feb 18 (Reuters) - Britain's top share index touched a 15-year high on Wednesday before edging lower, as the market alternated between concern that a ceasefire in Ukraine was crumbling and optimism that a deal over Greek debt was in reach.

The FTSE 100 index rose to 6,921.32, its highest since January 2000 and only 0.4 percent off the record high of 6,950.60 set in December 1999, then began to slip lower.

Technical analysts said that while the new peak could spur the market on towards a record high, a failure to close above 6,900 could see the market drop away again.

"This could turn out to be a false breakout for, after all, it is not the first time the FTSE has peaked above 6,900 only to then stage a sell-off," said Fawad Razaqzada, technical analyst at Gain Capital (NYSE: GCAP - news) . "A decisive close above 6,900 would be a particularly bullish outcome, while below this key level would be bearish."

By 1430 GMT it was down 18.11 points, or 0.3 percent at 6,880.02. Some traders cited mounting concern over in Ukraine as a reason.

Government forces started pulling out of a town in eastern Ukraine on Wednesday after a fierce assault by Russian-backed separatists which Europe said violated a ceasefire agreement.

"We see market risk led by Ukraine and geopolitics as among the key drivers for a move lower (in the FTSE)," Atif Latif, director of trading at Guardian Stockbrokers, said.

Coca-Cola Hellenic dropped 2.6 percent after the company reported a 11.4 percent drop in profits and on concern about developments in Ukraine. It has substantial exposure to Russia, which has seen sanctions imposed by the West over the conflict in Ukraine.

The FTSE 100 underperformed the euro zone's Euro STOXX 50 , up 0.5 percent after Greece said it intends to ask on Wednesday for an extension of its loan agreement with the euro zone.

Hopes that a deal might be struck to keep a financial lifeline for Greece, despite misgivings from international lenders, also helped to support UK-listed financials. The FTSE 100's loss would have been 6 points greater without gains by financial shares.

Among other gainers, Intercontinental Hotels (Other OTC: ICHGF - news) rose 2.2 percent, rebounding from a fall after its annual results on Tuesday.

Analysts said the share price was stretched after the hotel group reported results in line with forecasts, but the shares were buoyed on Wednesday by upgrades to its target price from UBS (LSE: 0QNR.L - news) and Jefferies. (Editing by Larry King)