LONDON, Oct 22 (Reuters) - Copper prices slipped on Thursday from the $7,000 mark hit in the previous session as investors waited to hear whether China would stockpile metals, and after another delay in agreeing a U.S. stimulus plan.

Some analysts and many investors are counting on top metals consumer China to announce plans to buy up copper and other metals to ensure enough future supply.

"One of the big questions for the metals markets that is underpinning prices at the moment is whether China announces a formal stockpiling plan, adding really to the bullish cocktail of good China news," said Kieran Clancy, assistant commodities economist at Capital Economics.

"What we're seeing now is that the rumors have been priced in, we've hit these technical levels, and so a pullback can be expected. We're in a wait-and-see mode."

Three-month copper on the London Metal Exchange was down 1% at $6,924 a tonne by 1600 GMT, having rebounded by about 50% since touching lows in late March.

Dampening sentiment on wider financial markets was U.S. President Donald Trump accusing Democrats of being unwilling to craft a compromise on a coronavirus stimulus bill.

* The global nickel market surplus narrowed to 6,600 tonnes in August from 8,400 tonnes the previous month, data showed.

* The Yangshan copper premium dropped to $54 a tonne, its first decline since Sept. 25, indicating lean demand for imported copper into China.

* The discount of cash LME aluminum to the three-month contract has declined further to $10.50 a tonne, the lowest since early March, indicating lower availability in LME warehouses.

* LME aluminum slipped 0.2% to $1,840 a tonne, nickel fell 0.4% to $15,825, zinc rose 0.2% to $2,573.50, lead shed 0.5% to $1,801 and tin declined 0.6% to $18,640. (Additional reporting by Mai Nguyen; Editing by Elaine Hardcastle, Susan Fenton and Jan Harvey)