  With the accurate cosmic ray (CR) electron and positron spectra (denoted as
$\Phi_{\rm e^{-}}$ and $\Phi_{\rm e^{+}}$, respectively) measured by AMS-02
collaboration, the difference between the electron and positron fluxes (i.e.,
$\Delta \Phi=\Phi_{\rm e^{-}}-\Phi_{\rm e^{+}}$), dominated by the propagated
primary electrons, can be reliably inferred. In the standard model, the
spectrum of propagated primary CR electrons at energies $\geq 30$ GeV softens
with the increase of energy. The absence of any evidence for such a continuous
spectral softening in $\Delta \Phi$ strongly suggests a significant `excess' of
primary CR electrons and at energies of $100-400$ GeV the identified excess
component has a flux comparable to that of the observed positron excess.
Middle-age but `nearby' supernova remnants (e.g., Monogem and Geminga) are
favored sources for such an excess.
