* China copper premiums at 18-month low
* GRAPHIC-2018 asset returns: http://tmsnrt.rs/2jvdmXl (Updates throughout, changes dateline from BEIJING)
LONDON, Dec 4 (Reuters) - Copper eased on Tuesday as markets awaited immediate action by the United States and China to de-escalate a damaging trade tariff dispute after the two countries agreed to a 90-day ceasefire at the weekend. But other metals held on to the previous session's gains, powered by a weaker dollar. At the G20 summit this weekend, Washington and Beijing agreed to hold off on imposing further tariffs for 90 days, pausing a dispute that dragged down metals and equity markets.
Markets were still skeptical, however, about a full resolution soon.
"The G20 has always been long on rhetoric and short on substance so we now we need to see some instant action taking place i.e. China agreeing to allow more U.S. imports of cars and open up their markets further," Societe Generale metals specialist Robin Bhar said.
The United States expects China to take immediate action to cut tariffs on U.S. car imports and end intellectual property theft and forced technology transfers as the countries move towards a broader trade deal, a White House official said on Monday.
Three-month benchmark copper on the London Metal Exchange (LME) fell 0.3 percent to $6,276 per tonne by 1115 GMT, after rising 1.6 percent on Monday.
FLOOR FOR METALS: "Initial G20 euphoria soon gave way to the realization that nothing has actually been resolved," Brokerage Marex Spectron said in a note.
"Weekend events probably raise the floor to the (metals) complex although whether that leads us to some sort of new panacea is highly debatable."
COPPER PREMIUMS: Premiums for imports of copper into China, the world's biggest copper consumer, sank to an 18-month low on Monday in a sign that demand for physical metal is waning after a buying spree.
TECK: Canadian mining company Teck Resources Ltd, agreed to sell a 30 percent stake in its Quebrada Blanca copper mine expansion in northern Chile to Japan's Sumitomo for $1.2 billion.
ALUMINIUM: A Japanese aluminum buyer has agreed to pay a global producer a premium of $85 per tonne over the benchmark price for shipments in January to March, the lowest in more than two years, two sources involved in pricing talks said on Tuesday.
OTHER METALS: Aluminium added 0.4 percent to $1,983 per tonne, zinc 1 percent to $2,610, lead 0.6 percent to $1,977, tin added 1.3 percent to $19,100 and nickel CMNI3> gained 0.9 percent to $11,355.
(Additional reporting by Tom Daly, editing by Ed Osmond)