Initial expansion (March-May 1948)
As mentioned above, the numbers of Islamic militias in the Priangan swelled from a few hundred to a few thousand in the short span between the beginning of the Siliwangi withdrawal until the end of March. This increase in number soon had consequences, especially as Hizboellah and Sabilillah were not the only irregular troops in the area, and the regular TNI had not completely evacuated the region.
In addition to clashing with TNI soldiers over weapons and supplies, throughout 1948 the troops of the Islamic Army also became engaged in a struggle to expand the territorial scope of the MOI-con- trolled areas at the expense of other guerrilla groups and the Dutch.
As territorial expansion had become a strategic priority, Karto- suwiryo and his military aides had divided West Java in three areas, depending on the degree of control that the Majelis held. The Dae- rah Satu (shortened in the original documents as D.I and meaning Region One) included villages controlled by the Darul Islam and implementing Islamic law. The Daerah Dua (D.II, Region Two) included the areas where the Darul Islam, the MOI or the TII had freedom of movement and strong influence. Lastly, the Daerah Tiga (D.III, Region Three) included those areas where the Darul Islam only had a limited degree of influence. According to this organizational scheme, in May ‘Region One’ included the area enclosed within Tasikmalaya, Ciawi, Panumbangan and Mount Sawal; the D.II encompassed the area between Cileungjji (Ciamis), Cisayong (Tasikmalaya), Nagrek, Darmarata, Talaga and Mount Sawal; and the D.III stretched eastward to Majalengka and Cikijing, and southeast to Lakbok, Parigi, Cikatomas and Tasikmalaya.
The Dutch attempt to cleanse Mount Sawal’s surroundings of Islamic fighters created considerable difficulty for the militias’ operations, but at the same time it provided the fighters with renewed strength and motivation. In retrospect, Dutch efforts to purge the Darul Islam from the Priangan were highly ineffective and mostly counterproductive. The Dutch Army had dispersed Islamic troops in Cikatomas, but this only resulted in the splitting of the militias between Cikalong (to the south) and Leuwisari (to the north). Similar attacks on the Mount Cupu area had spread Darul Islam soldiers to Cisayong, Ciawi, Indihiang and the southern districts. Further, Darul Islam troops had re-emerged in Pangerageung and Cineam, where they shared control of the territory with the communist Bamboe Roentjing militias.
As a result of the successful political guidance of Kartosuwiryo and the able military leadership of Kamran and Nur Lubis, the Darul Islam expanded widely. By May 1948 the Majelis Oemmat Islam- Darul Islam had established its territorial presence across the Prian- gan, while at the same time strengthening its political structure.
-  Qanun asasy Negara Islam Indonesia, AABRI DI no. 9; ‘Majelis Oemat Islam’, 12 August 1948,APG no. 997, NA, pp. 6-7; CMI Publication No. 91, 29 September 1948, AAS no. 3977, NA,pp. 8, 13.
-  CMI Publication No. 91, 29 September 1948, AAS no. 3977, NA.
-  ‘Tjatatan ringkas dari laporan2 jang ketrima antara tanggal 22 sampai 31 Agoestus 1948tentang kedjadian2 dalam kaboepaten Tasikmalaja’, 1 September 1948, APG no. 1080, NA.