BEIJING - Prices of tin rose on Thursday after the International Tin Association confirmed a ban on mining by Myanmar's ethnic minority Wa militia from Aug. 1.

Three-month tin on the London Metal Exchange CMSN3 gained as much as 3.8% in the Asian morning trading session and was up 0.7% to $27 595 per metric ton by 07:57 GMT.

The most-traded September tin contract on the Shanghai Futures Exchange SSNcv1 ended day-time trade 1.3% higher to 229 920 yuan ($319 63.52) per metric ton.

"We have confirmation that Wa State mines were closed on August 1 as mandated," the ITA told Reuters on Wednesday.

The ban was announced in April when it immediately boosted prices of the metal that is used in the electronics and semiconductors sectors. The duration of the ban is not known.

The Wa region is estimated to have accounted for over 70% of Myanmar's tin production in 2022, and Myanmar is the world's third biggest in terms of tin reserves.

The ITA said in a statement issued on Thursday that previous market expectations of one to three months for the suspension "now seem overly optimistic", and it may also take longer to re-open mines.

The ban's short-term impact had been priced in, but the lasting supply disruption and steady demand outlook will support tin prices, said analysts at Orient Securities.

Despite supply concerns, weighing on the market was a strong dollar, making it less attractive to buy the greenback-priced commodity.

Most other metals on SHFE lost. Copper SCFcv1 slid 1.3% to 68 860 yuan a metric ton, aluminium SAFcv1 eased 0.4% to 18 460 yuan, zinc SZNcv1 dropped 1.6% to 20 800 yuan, lead SPBcv1 was down 0.1% at 15,925 yuan and nickel SNIcv1 fell 2.8% to 167 580 yuan.

LME copper CMCU3 lost 0.4% to $8 477.50 a metric ton, zinc CMZN3 declined 0.8% to $2 462.50, lead CMPB3 slipped 0.4% to $2,137, while nickel CMNI3 shed 0.3% to $21,495, aluminium CMAL3 gained 0.1% at $2 212 a metric ton.