In the late 1990s, UN-authorised international interventions took a wider variety of forms. The UN mission in the 1991–2002 Sierra Leone Civil War was supplemented by British Royal Marines, and the UN-authorised 2001 invasion of Afghanistan was overseen by NATO. In 2003, the US invaded Iraq despite failing to pass a UN Security Council resolution for authorization, prompting a new round of questioning of the organization's effectiveness. In the same decade, the Security Council intervened with peacekeepers in crises including the War in Darfur in Sudan and the Kivu conflict in the Democratic Republic of Congo. In 2013, an internal review of UN actions in the final battles of the Sri Lankan Civil War in 2009 concluded that the organization had suffered "systemic failure".