Russia begins the Second Chechen War in response to the Invasion of Dagestan by the Islamic International Peacekeeping Brigade.

The Second Chechen War took place in Chechnya and the border regions of the North Caucasus between the Russian Federation and the breakaway Chechen Republic of Ichkeria, from August 1999 to April 2009.

The 1999 war in Dagestan, also known as the Dagestan incursions, was an armed conflict that began when the Chechen-based Islamic International Peacekeeping Brigade (IIPB), an Islamist group led by Shamil Basayev, Ibn al-Khattab, Ramzan Akhmadov and Arbi Barayev, invaded the neighboring Russian republic of Dagestan on 7 August 1999, in support of the Shura of Dagestan separatist rebels. The war ended with a major victory for the Russian Federation and Republic of Dagestan and the retreat of the IIPB. The invasion of Dagestan alongside a series of apartment bombings in September 1999 served as the main casus belli for the Second Chechen War.

The Islamic International Peacekeeping Brigade, also known as the Islamic International Brigade and the Islamic Peacekeeping Army, was the name of an international Islamist mujahideen organization founded in 1998. IIPB was designated a terrorist entity by the United States in February 2003.