Japan Post has announced that it will expand the number of countries and regions that temporarily suspend the acceptance of international mail to 160 countries from April 10 (Fri). Newly added countires are Sweden, Denmark, Norway, Australia, etc.
You can check/download a complete list of countries here.
Also, due to the significant reduction and suspension of flights, it is expected that international mail destined for the United States will require more than two weeks to be loaded onto the airplanes.