Former series (1980-2003) Diplomatic plates where coloured blue on white with four digits and a class sticker with “DC” for diplomatic plates.

United States Forces in Philippines

1970-1980 series non-diplomatic Embassy Staff.
At the bottom left was E for tax exempt or E and a vehicle category letter.
In this case H = Heavy car. Than US EMBASSY (1970-1973)
or US EMB (1974 – 1977)