They are by Israeli ceramicist Ruth Faktorowicz, who signs her work J. Ruth. She was born in 1937, and studied under Israeli ceramicist Zohar Guri, who's Modernist style clearly influenced Ruth's style. Ruth also studied at the Ramat-Gan Art School 1973-1975.
J. Ruth's work often depicts themes of peace, family and friendship, and also the townscapes of Israel. You can see more of here work on this U.S. based gallery site.