Copper prices eased on Wednesday as tariff worries countered stronger-than-expected U.S. jobs data, while focus stayed on U.S. President Donald Trump's trade negotiations.

Three-month copper on the London Metal Exchange was down 0.2% to $9,619 per metric ton in official open-outcry trading.

Trump signed an executive proclamation that puts into effect from Wednesday his surprise announcement last week that he was taking the tariffs on steel and aluminum imports that had been in place since March to 50% from 25%.

Wednesday is also when the White House would like trading partners to submit their proposals for deals that might help them avoid Trump's hefty "Liberation Day" tariffs from taking effect in five weeks.

Providing support, the U.S. dollar wobbled, making metals more affordable for holders of other currencies.

Meanwhile, job openings, a measure of labor demand, rose 191,000 to 7.391 million by the last day of April, the Labor Department's Bureau of Labor Statistics said in its Job Openings and Labor Turnover Survey, or JOLTS report, on Tuesday.

"Yesterday's JOLTS, which was better than expected, leaves markets surprised by the resilience of the U.S. economy," said Alastair Munro at broker Marex.

LME copper also benefited from continued outflows from LME-registered warehouses. LME's daily data showed inventory fell to 141,350 tons, a near one-year low, after 2,500 were delivered out.

The latest metal tariffs have renewed focus on the ongoing U.S. investigation into potential new copper import duties, aimed at boosting domestic production. This has pushed COMEX copper prices above LME levels, prompting traders to reroute copper supplies to the U.S. to take advantage of the price gap.

LME tin gained 2% to $32,000, aluminium firmed 0.5% to $2,475.5 a ton, zinc slipped 0.1% to $2,705, nickel was up 0.3% to $15,480, and lead inched up 0.1% to $1,987.

(Reporting by Ashitha Shivaprasad in Bengaluru; Editing by Vijay Kishore)