Kobe Steel Ltd. tumbled as much as 13 percent in Tokyo to hit the lowest level in almost seven years after Japan's third-biggest steelmaker swung to a first-quarter loss and warned that full-year profit will collapse.

The shares sank the most since 2017 after the company posted a ¥1.2 billion net loss in the three months to June 30 and forecast full-year net income will drop 72 percent. The impact of the U.S.-China trade war "has become apparent and the outlook is growing uncertain," Yoshihiko Katsukawa, senior managing executive officer, said at a briefing in Tokyo on Friday.

Steelmakers around the world are facing a bleaker outlook as growth slows, trade-war risks escalate and they seek to manage costs after a first-half surge in iron ore. Fellow Japanese mill Nippon Steel Corp. tumbled the most in more than eight years Friday after forecasting full-year business profit will tank, and industry giant ArcelorMittal has cut its estimates for global demand.