The city of residence is located at the West Bank's "waist", which means that an expansion can divide the Palestinian area into two parts.
Thwarting a Palestinian state is an explicit goal for far-right parties in Israel, and Smotrich's press release has the title "To bury the idea of a Palestinian state", reports the news agency Reuters on its website.
However, it is unclear whether Smotrich has a mandate to approve the expansion, and if he has the support of Prime Minister Benjamin Netanyahu.
Ma'ale Adumim was founded in the 70s, and today has over 30,000 inhabitants. It has not yet been built out so much that the northern and southern West Bank are separated from each other. But it is considered a foundation for a Palestinian state formation that Ramallah, north of Jerusalem, and Bethlehem, south of it, are geographically connected.