* FTSE 100 falls 0.7 percent, touches six-week low
* Banks, commodity stocks fall
* Precious metal miners gain ground
By Simon Falush
LONDON, Nov 23 (Reuters) - Britain's top shares fell to a six-week low on Tuesday, with banks and miners hit hardest, dented by fears the euro zone debt crisis could escalate and after an exchange of artillery fire in the Korean peninsular.
The FTSE 100 was down 38.53 points or 0.7 percent at 5,642.30 by 1202 GMT, after closing 0.9 percent lower at a three-week trough on Monday. It earlier fell to a 5,614.65, its lowest since early October.
North Korea fired dozens of artillery shells at a South Korean island, killing two soldiers and prompting a return of fire by the South.
This further unnerved investors already anxious about the euro zone debt situation, and prompted selling of riskier assets like banks.
Barclays, Standard Chartered and Lloyds Banking Group fell 0.8 to 1.7 percent.
However, while the index has fallen for each of the last three weeks, it is down only 0.3 percent on the month and is still 18 percent higher than the year's low touched on July 1.
"There are plenty of reasons to take profits, but profits are not being taken that aggressively," John Haynes, head of research at Rensburg Sheppards, said.
"(Equities are) holding up remarkably well in the face of a lot of provocation, there's a recognition that there is the will to solve (Europe's debt) problems."
Ireland's government was on a knife-edge on Tuesday with damaged Prime Minister Brian Cowen challenging the opposition to let an austerity budget pass and trigger an EU/IMF bailout before early elections.
European partners and the International Monetary Fund agreed in principle on Sunday to rescue Ireland with an expected 80 billion to 90 billion euros in loans to tackle a banking and budget crisis.
GEOPOLITICAL JITTERS
The geopolitical uncertainty combined with euro zone jitters helped push the dollar higher, hitting metal and crude prices and denting miners and energy stocks.
Rio Tinto lost 1.3 percent while Royal Dutch Shell slipped 0.9 percent.
Gold miner Randgold Resources bucked the trend, gaining 0.9 percent as the price of the yellow metal firmed on geo-political uncertainty.
TUI Travel added 3.7 percent, with traders citing a report that parent TUI is talking to investor John Fredriksen over its stake in shipping firm Hapag-Lloyd.
Rolls-Royce was another significant gainer, pushing 2 percent higher as the engineer benefited from news that Qantas will resume A380 flights after an engine failure crippled a jet carrying 466 people earlier this month.
On the other side of the Atlantic, the first revision for U.S. Q3 GDP is due at 1330 GMT, U.S. October existing home sales data are due at 1500 GMT, with the latest FOMC meeting minutes at 1900 GMT.
Things are starting to look more bearish from a technical standpoint, said Nicole Elliott, analyst at Mizuho Corporate Bank.
"The weekly candles are currently three consecutive down ones (with black bodies) so might be 'three black crows'," she said. "Pivotal support lies at 5,470; note how we collapsed through there in May. On daily chart 10- and 20-day moving averages look set to cross to a sell today." (Editing by Michael Shields)