original_query: What were the main causes of the Dagestan War in 1999?
query: What were the main causes of the Dagestan War in 1999?
answer: The main causes were the invasion of Dagestan by Chechen-based Islamist groups, led by Shamil Basayev and Ibn al-Khattab, aiming to establish an Islamic state;  long-term tensions between Chechnya and Russia, including the unresolved issues from the First Chechen War; and the ambition of creating a union of Chechnya and Dagestan under Islamic rule.