Block from U+A840 to U+A87F. This block was introduced in Unicode version 5.0 (2006). It contains 56 codepoints.
The Wikipedia provides the following information on block Phags-pa:
Phags-pa is a Unicode block containing characters from the 'Phags-pa script promulgated as a national script by Kublai Khan. It was used primarily in writing Mongolian and Chinese, although it was intended for the use of all languages of the Mongol Empire.