U.S. President Donald Trump's trade war with China is causing a flight to safety in currency markets, and the yen is once again taking the brunt of it.

The currency surged Monday to its highest level against the dollar in seven months, fueling fears in some quarters that the volatility may put the brakes on global growth.

The Japanese government is no less spooked. On Monday it held an emergency meeting with finance chiefs to discuss the yen's strength.