TOKYO, April 6 (Reuters) - Japanese stocks were choppy on Friday morning as the perceived safe-haven yen rose after U.S. President Donald Trump warned of further tariffs on China as the simmering trade dispute between the two nations kept investors on edge.
The Nikkei share average edged up 0.1 percent to 21,677.72 in midmorning trade, after trading in and out of the black in early deals.
For the week, the index has gained 0.8 percent so far.
Trade tensions returned to the fore after Trump said late on Thursday that he had instructed U.S. trade officials to consider $100 billion in additional tariffs on China, keeping the trade dispute between the world's two economic superpowers on the boil.
U.S. stock futures fell on the latest news as investors fretted about the damaging impact of a full-scale U.S.-China trade war on global trade and economic growth.
In Asian trade, The dollar fell 0.2 percent to 107.15 yen , pulling away from a one-month high of 107.49 yen set on Thursday.
S&P 500 e-mini futures were down 1.4 percent in trading for the overnight session, while Dow futures were down 1.7 percent, hurting sentiment in Japanese shares.
"The market struggles to digest what's going on with trade issues between the U.S. and China," said Hikaru Sato, a senior technical analyst at Daiwa Securities. "It's hard to make investment decisions when news linked to this issue comes out during Asian trading hours so investors are just refraining from taking positions."
Markets are also focused on cues from U.S. jobs data and comments by Federal Reserve Chairman Jerome Powell later on Friday.
Shippers underperformed after the baltic dry index, or freight charges, fell overnight. Mitsui OSK Lines dropped 0.9 percent and Kawasaki Kisen fell 1.3 percent.
Technology stocks lost ground, with Advantest Corp falling 2.8 percent and TDK Corp shedding 0.8 percent.
Supermarket operator Seven & i Holdings surged more than 4 percent after the company expected a 6 percent rise in its operating profit to 415 billion yen for the fiscal year ending February 2019, an eighth straight year of record profit.
The broader Topix was flat at 1,724.20. (Reporting by Ayai Tomisawa Editing by Shri Navaratnam)