Copper prices continued to rise on Tuesday, hitting their highest level in three weeks, supported by signs of improved demand and tight supply in China, the world's largest metals consumer, along with escalating concerns about potential supply chain disruptions due to tensions in the Middle East.

The benchmark three-month copper price on the London Metal Exchange rose 0.4 percent to $13,601 per metric ton by 09:30 GMT, its highest since June 23.

Eva Manthey, commodities strategist at ING Bank, said: "Copper is getting support from a mix of strong Chinese export data and tight physical market conditions."

Official data showed that China's exports, the world's largest metals consumer, rose notably in June, posting their best performance in four months.

The most-traded copper contract on the Shanghai Futures Exchange also rose 1.1 percent to 104,390 yuan per ton.

Manthey added that "the rise in Chinese premiums and the decline in exchange inventories indicate increasing tightness of spot supply."

The premium paid by spot market buyers over Shanghai copper futures prices rose to 215 yuan per ton, compared with zero at the end of June, the highest since late February.

Metals markets also benefited from a weaker dollar index, making dollar-denominated commodities cheaper for buyers using other currencies.

Supply fears support prices

The escalation of the Iranian conflict has renewed fears about sulfur supplies, posing a risk to copper and nickel supply chains, as sulfuric acid derived from sulfur is used in copper extraction.

In other metals markets, aluminum on the London Metal Exchange rose 0.2 percent to $3,177 per ton, while nickel stabilized at $16,765.

Zinc rose 0.5 percent to $3,582 per ton, and tin rose 1.8 percent to $53,525 per ton.

In contrast, lead fell 0.5 percent to $1,859.50 per ton, after a jump in LME inventories of 80,700 tons, or 28 percent, following the arrival of new shipments to Singapore warehouses.