* Futures down: Dow 0.20 pct, S&P 0.18 pct, Nasdaq 0.10 pct
By Shreyashi Sanyal
Aug 31 (Reuters) - U.S. stock index futures fell on Friday, ahead of the long holiday weekend, with investors wary after President Donald Trump's latest salvo in Washington's trade war with China.
Wall Street snapped a four-day winning streak on Thursday after Bloomberg reported Trump was ready to impose tariffs on $200 billion more of Chinese goods next week, sooner than many expected, when a public comment period on the plan ends.
The U.S.-China dispute has overshadowed what has been intense, but constructive trade negotiations between the United States and Canada, although a deal is yet to be struck.
"The threat of global growth taking a hit from a damaging U.S-China relationship remains 'front and center'," said Dean Popplewell, vice president of market analysis at Oanda.
Traders also cautioned markets could be susceptible to bigger-than-usual gyrations as trading volumes are expected to be light ahead of the long Labor day holiday weekend.
At 7:31 a.m. ET, Dow e-minis were down 52 points, or 0.20 percent. S&P 500 e-minis were down 5.25 points, or 0.18 percent and Nasdaq 100 e-minis were down 7.75 points, or 0.10 percent.
Shares of Coca-Cola rose 0.8 percent in premarket trading after the company said it would buy coffee chain Costa for $5.1 billion. Starbucks fell 2.3 percent.
Lululemon was up 10.4 percent after the Canadian athletic apparel maker posted a second-quarter profit that beat estimates on strong online sales, particularly in China.
Apple gained 0.3 percent. Warren Buffett said Berkshire Hathaway had added to its stake in the iPhone maker and Apple announced a Sept. 12 event, at which it is expected to unveil new iPhone models.
Amazon.com was up 0.2 percent, topping $2,000 for the second day in a row to renew its push to join Apple in the $1 trillion market cap club.
Integrated Device Technology jumped 15 percent after Japanese automotive chipmaker Renesas Electronics said it was considering buying the U.S. chipmaker.
The University of Michigan's consumer sentiment index for August is expected at 10 a.m. ET. (Reporting by Shreyashi Sanyal in Bengaluru; Editing by Shounak Dasgupta)