London aluminium prices sank to a 16-month low on Thursday after the United States said it would withdraw sanctions on Russian aluminium giant Rusal in one month.

"We didn't expect the U.S. to lift the sanction on Rusal this early, but aluminium market has largely discounted the lifting for some time," Hideya Kitamura, general manager at Marubeni's light metals section, told reporters on Thursday.

"Aluminium prices are likely to recover next year amid a supply shortage, and premiums are expected to climb above $100 a tonne in and after April when demand usually picks up," he said.

Japan is Asia's top aluminium importer and the premiums for primary metal shipments it agrees to pay each quarter over the London Metal Exchange (LME) cash price set the benchmark for the region.

The premiums that are now being negotiated between the country's buyers and global producers will likely settle at $85 per tonne for January-March quarter and reach $90-$120 in April-June and $100-$130 in the later half of 2019, the Japanese trading house said.

"Since the actual costs to bring the metals to Japan, including shipping fees and insurance, are about $90-$95 a tonne, we don't think the premiums would fall from the current levels," Kitamura said.

Some Japanese aluminium buyers have agreed to pay global producers a premium of $85 per tonne over the LME cash price for shipments in January to March, the lowest in more than two years, four sources involved in pricing talks said this week.

Three-month aluminium on the London Metal Exchange on Thursday dropped as much as 1.1 percent to $1,905.50 a tonne, the lowest since Aug. 4, 2017, after the report on Rusal.

However Marubeni, a major Japanese aluminium trader, expects the metal prices to rebound next year, with an average prices between $2,000 and $2,100 in the first half of next year, followed by $2,100-$2,250 in the second-half.

A global aluminium market will see a deficit of 1.38 million tonnes next year, against a shortage of 1.72 million tonnes this year, amid solid demand for the light metals in automobiles.

(Reporting by Yuka Obayashi, Editing by Sherry Jacob-Phillips)

By Yuka Obayashi