(Updates prices, adds comment, changes dateline to London)

By Polina Devitt

LONDON, Aug 11 (Reuters) - Aluminium prices climbed to a

seven-week high on Tuesday as concerns over supply from the Gulf

coincided with Norsk Hydro's ( NHYKF ) announcement of reduced feedstock

production at its Brazilian plant.

Benchmark three-month aluminium on the London Metal

Exchange was up 1.9% to $3,378.50 a metric ton at 0850 GMT,

after hitting $3,382.5, its highest since June 22.

Aluminium extended its gains to a seventh consecutive

session after Norsk Hydro ( NHYKF ) said its Alunorte plant in

Brazil had cut alumina output to 50% of capacity due to reduced

supply of natural gas. The plant has annual production capacity

of 6.3 million tons of alumina.

Aluminium is up 6% so far in August, having broken above its

200-day moving average last week, which now provides support at

$3,219. The next resistance level is the 100-day moving average

at $3,396.

"Aluminium had a lot of resistance at $3,200. Once it got

through there, it was only a matter of time until it started to

trend higher," said a metals trader. "Any bullish headline just

acts as a catalyst and adds fuel to the fire."

Providing further support are worries about supply from Gulf

producers and rising oil prices as negotiations between the

United States and Iran over a peace deal and the reopening of

the Strait of Hormuz hit an impasse.

The U.S.-Iran war has disrupted aluminium shipments from

producers in the Middle East, which account for 9% of global

capacity.

Meanwhile, available aluminium stocks in LME-registered

warehouses are at 244,550 tons, the lowest since April 2025,

dominated by Russian-made metal, which many traders avoid.

In other LME metals, copper rose 0.3% to $14,195,

having closed on Monday at an all-time high of $14,160 as

outflows to the U.S. ahead of potential U.S. import tariffs

reduced availability.

The cash-to-three-month spread on the LME remains

in sharp backwardation at $145.5 a ton, signalling tightness for

nearby supply.

LME zinc fell 0.3% to $3,723.50, while tin

gained 0.4% to $55,750. Lead and nickel added

0.1% to $1,904 and $16,925, respectively.