Former AGP president Chandra Mohan Patowary and senior AGP leader and former minister Hitendra Nath Goswami joined BJP and were welcomed by BJP President Rajnath Singh.
In another development, Gorkha Janmukti Morcha (GJM) President Bimal Gurung announced his outfit will extend support to BJP in West Bengal.
He was accompanied by two of the Morcha's general secretaries Raju Pradhan and Vinay Tamang.
"Besides individuals who are consolidating BJP after leaving other parties in several states, the next few days are going to be extremely important in terms of BJP and NDA consolidating on the present situation in the three southern states of Karnataka, Andhra Pradesh and Tamil Nadu.
"These developments will add to the strength of BJP in eastern and southern parts of India where BJP traditionally was not a strong political force," Jaitley said in an article.