* Zinc inventories within 2,000 tonnes of 2004 peaks
* Aluminium hits new 2.5 year highs
* Lead premium for tomorrow/next day delivery flares up
(Adds analyst comment, closing prices)
By Silvia Antonioli and Melanie Burton
LONDON, April 19 (Reuters) - Copper rose more than 1 percent on Tuesday, clawing back some ground after six straight sessions of losses as risk sentiment improved and the focus shifted to long-term supportive fundamentals.
But investors remained nervous about debt problems in the United States and Europe.
Three-month copper on the London Metal Exchange closed at $9,340 from $9,225 at the close on Monday, while aluminium nudged to new two-and-a-half year highs.
In the previous session, copper fell almost 2 percent to its lowest in a month.
"The market panicked a bit yesterday, and they're feeling a little less panicked today," said BNP Paribas analyst Stephen Briggs.
"The reserve requirement rise in China and the S&P move was something (metals) had to react to, but the default position is that things are not as bad as all that."
Standard & Poor's threatened on Monday to downgrade the U.S. AAA credit rating, raising concerns over the debt situation of the world's largest economy and second-largest consumer of copper.
Earlier this week, China's central bank announced an increase in bank reserve requirement ratios.
"Yesterday the bombshell of the U.S. downgrade caused mayhem in the market. Today copper bounced back, supported by technicals but it is still vulnerable," an LME ring trader said.
A report that Greece may have to restructure its debt also weighed on market confidence.
But world markets bounced back from the previous session's trouncing after better-than-expected earnings results from investment banking bellwether Goldman Sachs.
In the metals markets, expectations of a supply deficit this year and an optimistic long-term demand outlook provided support.
"The physical market looks quite good despite high inventory levels," said Daniel Briesemann, an analyst at Commerzbank.
"We expect China to be a stable market player over the next few months. We certainly do not expect demand from China to collapse."
COPPER CONTANGO
Increasing copper inventories, however, have raised concerns about some short-term demand weakness from China.
Inventories of copper on the London Metal Exchange rose 175 tonnes to 451,950 tonnes, its highest since June, the latest data showed. Inventory levels have been on the rise since December.
"In a market that is supposedly in deficit, it remains unclear why copper inventories held on exchange have been increasing," said Bernstein Research in a note.
Either demand for copper is lower than expected, off-exchange inventory is being moved on-exchange, or supply is greater than expected, it said.
"Two of these three possible reasons would imply that there is a significant downside to copper prices from current levels."
Aluminium rebounded to $2,714 from $2,674, having hit $2,724, the highest since August 2008 in the aftermarket.
The metal used in transport, packaging and construction has been boosted by rising power prices, which account for about 35 percent of total aluminium smelting costs.
Tin ended at $32,400 from $32,350, while zinc closed at $2,329 from $2,325, Monday's close.
Inventories of zinc on the London Metal Exchange rose 21,300 tonnes to 785,600, the most recent data showed, and are now within 2,000 tonnes of 2004 peaks.
Battery material lead finished at $2,557 from $2,528. The price of metal for tomorrow versus next day delivery traded as high as $10, indicating a lack of immediately available supply.
Senior traders said on Tuesday that Barclays Capital was holding a dominant position in the lead market, controlling 80-90 percent of lead stock warrants and cash contracts on the London Metal Exchange.
Barclays declined to comment.
Nickel closed at $25,300 from $25,500.
Metal Prices at 1644 GMT Comex copper in cents/lb, LME prices in $/T and SHFE prices in yuan/T Metal Last Change Percent Move End 2009 Ytd Percent
move COMEX Cu 423.55 3.75 +0.89 334.65 26.57 LME Alum 2714.00 40.00 +1.50 2230.00 21.70 LME Cu 9340.00 115.00 +1.25 7375.00 26.64 LME Lead 2557.00 29.00 +1.15 2432.00 5.14 LME Nickel 25295.00 -205.00 -0.80 18525.00 36.55 LME Tin 32395.00 45.00 +0.14 16950.00 91.12 LME Zinc 2329.00 4.00 +0.17 2560.00 -9.02 SHFE Alu 16705.00 -165.00 -0.98 17160.00 -2.65 SHFE Cu* 69440.00 -1520.00 -2.14 59900.00 15.93 SHFE Zin 17680.00 -745.00 -4.04 21195.00 -16.58 ** Benchmark month for COMEX copper * 3rd contract month for SHFE AL, CU and ZN SHFE ZN began trading on 26/3/07
(Editing by Alison Birrane and Jane Baird)