LONDON: Copper slipped on Friday as speculators bet a rally had extended too far since demand in top consumer China is likely to struggle and after US coronavirus cases hit record levels.

Copper has been the top gainer on the London Metal Exchange in recent months, rebounding 40% from late March to a peak of more than five months on Thursday, partly on concern about supply from top producer Chile.

"The technical indicators are flashing overbought conditions and there are signals that global growth is stalling after the strong recovery we've had," said Gianclaudio Torlizzi, partner at consultancy T-Commodity in Milan.

The relative strength index, a key indicator for investors relying on chart signals, rose to about 75 on Thursday, over the 70 level regarded as indicating a potential reversal.

Three-month LME copper was down 0.8% at $6,027 a tonne by 1038 GMT after touching $6,120 on Thursday, its highest since Jan. 22.

Copper was heading for a weekly gain of about 1%, its seventh consecutive weekly rise, the longest winning streak in nearly three years.

"The price needs to cool down, but if it stays above $5,400, it's still a buy. I hope that we're going to have pullback of about $500," Torlizzi said, adding that he had gone short on copper.

The United States reported a new daily global record of cases for the coronavirus pandemic, while top copper consumer China is entering its summer construction slowdown, which will crimp demand.

TC/RCs: China's top copper smelters set their floor treatment and refining charges for the third quarter at $53 per tonne and 5.3 cents per pound..

NICKEL/STAINLESS: Nickel hit the highest since Feb. 18, gaining 1.3% to $13,120 a tonne, after Shanghai stainless steel futures hit a six-week high.

The bulk of nickel is used in the production of stainless steel.

PRICES: LME aluminium gave up 0.2% to $1,617.50 a tonne, zinc shed 0.9% to $2,027, lead fell 0.7% to $1,769 and tin added 0.1% to $16,850.