Not out of the box. The final product needs to be compiled (iOS) or in bytecode (Android). Since it may be possible to convert Python code to Objective-C or something in between it might be possible.
See Kivy — the previous thread referenced it. This allows you to write you app in Python but probably uses a common wrapper (that Kivy provides) to run Python.
Please note that code written in Objective-C (iOS) or Java (Android) will always be faster than middle-ware like Kivy or Phonegap. Unless the one developing is very bad at writing any of those native languages....
