The negative figures on the stock markets come after the US attacked Iranian launch sites on the island of Larak in the Strait of Hormuz. Oil prices also rose on Monday, and Brent crude was trading at around $90 a barrel at 4 a.m.
Tokyo's Nikkei 225 is down 1.6 percent while the broader Topix is down 0.5 percent.
South Korea's Kospi index is down 2.2 percent.
Chinese stock markets are also in the red. Shenzhen is down 1.2 percent and the Shanghai stock market is down 0.4 percent.
The Hong Kong-based Hang Seng is down 0.9 percent.
