We show that the Iancu-Mueller factorization has a simple interpretation in
the Reggeon - like technique based on the BFKL Pomeron. The formula for
calculating the high energy asymptotic behaviour for the colour dipole-dipole
amplitude is proposed which suggests a procedure to calculate this amplitude
through the solution to the Balitsky-Kovchegov non-linear equation. We confirm
the Iancu - Mueller result that a specific set of enhanced diagrams is
responsible for the high energy behaviour for fixed QCD coupling. However, it
is argued that in the case of running QCD coupling, this asymptotic behaviour
originates from the Balitsky-Kovchegov non-linear equation. A new solution to
the non-linear equation is found which leads to a different asymptotic
behaviour of the scattering amplitude even for fixed QCD coupling..Comment: 27 pages, 9 figuure