Karimov had originally cultivated Islamic symbols after independence in order to coopt religious opposition. In May 1999, as a response to the threat of Islamic radicalism, the Oliy Majlis revised the 'Law on Freedom of Conscience and Religious Organizations' to impose new restrictions on religious groups. The construction of mosques, for example, required permission and specific documentation. An assassination attempt on Karimov in 1999 elicited even more repression of Islamic groups. After the September 11 attacks in 2001, Uzbekistan was considered a strategic ally in the United States' "War on Terror" campaign because of a mutual opposition to the Taliban. Uzbekistan hosted an 800-strong U.S. troop presence at the Karshi-Khanabad base, also known as "K2", which supported U.S.-led efforts in the 2001 invasion of Afghanistan. The move was criticized by Human Rights Watch which said the U.S. government subordinated the promotion of human rights to assistance in the War in Afghanistan. U.S.-Uzbek relations deteriorated in May 2005 when Karimov's government strongly encouraged the abandonment of the U.S. base in the face of U.S. government criticism of the government killings of protestors in Andijan. In July 2005 U.S. military forces left Karshi-Khanabad.