By 1958, despite an economic recovery and the unexpected success of U Nu's 'Arms for Democracy' offer that saw the surrender of a large number of insurgents, most notably the PVO, the AFPFL had become riven with internal splits, which worsened following the party's congress in January 1958. In July 1958 it formally split, with one group led by Prime Minister U Nu, which he named the "Clean AFPFL"; the other was led by Kyaw Nyein and Ba Swe and was known as the Stable AFPFL.