Have seen that mark several times over the years, always on fairly heavy and well made Scandinavian-inspired pieces (I have the same sugar and creamer), they are almost certainly mid 20th century American. So far as I know the manufacturer remains a mystery. See second down in the middle column on the link below:
http://www.925-1000.com/americansilver__Unk.html" onclick="window.open(this.href);return false;
~Cheryl