Recasts with analyst comment and updated prices, adds dateline

By Eric Onstad

LONDON, March 7 (Reuters) - Copper prices slipped on Friday on weak trade data from top metals consumer China, selling by miners and as investors reduced positions amid volatile changes in U.S. tariff policy.

Benchmark three-month copper on the London Metal Exchange (LME) CMCU3 was down 0.5% at $9,684 a metric ton by 1100 GMT while U.S. Comex copper futures HGc3 shed 0.6% to $4.78 a lb.

LME copper touched its highest in four months on Thursday at $9,739 a ton on a weak dollar and after U.S. President Donald Trump relaxed his tariffs on Canada and Mexico.

The upbeat sentiment carried over to Asian trading on the Shanghai Futures Exchange, where copper SCFcv1 hit a five-month peak, but it pared gains to end the session up 0.3%.

Prices pulled back on fresh worries about the world's second-largest economy after data showed Chinese imports unexpectedly shrank over January-February, while exports lost momentum and China's trade surplus with the United States grew.

In addition, China's unwrought copper imports declined by 7.2% year-on-year to 837,000 metric tons in the same period.

"The weak Chinese imports are raising a question over the real state of their domestic economy and the trade surplus is only going to raise the likelihood of more tariffs," said Alastair Munro, senior base metals strategist at broker Marex.

Investors were also shedding positions ahead of the weekend, wary of unexpected news that could hit prices, he added.

"Given all the uncertainty, we live in a much higher frequency trading world. Now you've got a lot of people who don't want to carry risk over the weekend."

With LME copper set for a rise of 3.4% this week, copper producers have been selling to lock in the higher prices, Munro said.

Helping support the market was a weaker dollar index .DXY, which is on course for its worst weekly performance since the week in November when Trump won the U.S. election. FRX/

A softer dollar makes commodities priced in the U.S. currency less expensive for buyers using other currencies.

LME aluminium CMAL3 edged up 0.1% to $2,700 a ton and nickel CMNI3 was little changed at $16,305 while zinc CMZN3 lost 0.4% to $2,918, lead CMPB3 dropped 1.2% to $2,024 and tin CMSN3 eased 0.3% to $32,480.

($1 = 7.2446 yuan )

(Reporting by Eric Onstad; Editing by Mrigank Dhaniwala)

((eric.onstad@thomsonreuters.com; +44 20 7542 7093; Twitter https://twitter.com/reutersEricO; Reuters Messaging: eric.onstad.thomsonreuters.com@reuters.net))