In the latter part of May, 1902, Gruev was condemned to banishment in the prison of Podroum-Kale in Asia Minor. There he found Christo Matov and Dr.Christo Tatarchev, both sentenced to exile in January 1901. Gruev and his comrades were kept in Podroum-Kale for ten months. Although he was away from Macedonia itself, Gruev managed to keep himself informed as to the development and affairs of the IMRO. He kept up a steady correspondence, ciphers also, with Salonica, Monastir, and Sofia. On Easter of 1903, at the instance of a general amnesty, he was released. Gruev hastened to Salonica and there he found the that the Central Committee, which was in charge of the IMRO, had already resolved to declare a general insurrection which was to take place during 1903.Although Gruev was not in accord with the Central Committee’s decision, primarily because of the IMRO’s lack of preparedness, since it was too late to oppose or to follow any other method, he gave in to the decision of the central Committee.
He left Salonica and went to Smilevo where the insurrectionary Congress was to be held. The purpose of this Congress was to set the date for the declaration of the general insurrection and to outline the methods and tactics in its prosecution. Here Gruev met Boris Sarafov, who had just arrived from Bulgaria. Gruev was elected as chairman of this Congress, and the latter decided that the day of the declaration of the insurrection was to be August 2, 1903. Gruev, Sarafov, and Alexander Lozantchev were elected by the Congress as the three members of the General Staff, and empowered to direct the insurrectionary forces in the Vilayet of Monastir.