Though Vadalov played no role in the 1999 Dagestan incursion led by Shamil Basayev and Ibn al-Khattab, following Russia's re-invasion of Chechnya that autumn he joined Khattab's Arab Mujahideen in Chechnya. After engaging in the battles for Argun and Gudermes, Vadalov's unit withdrew to the mountainous districts of Vedeno and Nozhay-Yurt in order to launch guerrilla attacks on Russian security forces.