Upping the ante in its rankling, tit-for-tat trade war with China, the government could soon begin procedures to formalize emergency import restrictions on three Chinese farm products, government sources said Wednesday.

The decision whether to do so will likely come in September, and the formal restrictions would likely take effect in November and remain for two years.

The sources said, however, that Japan will continue to pursue a settlement through negotiations before the current 200-day preliminary "safeguard" restrictions expire on Nov. 8.