The IMU resumed offensive operations in the summer of 2001, with locally based sleeper cells attacking two military posts on the Kyrgyzstan–Tajikistan border and a Kyrgyz television transmitter in late July. The attacks suggested that Namangani wielded "a new, independent command structure that could operate without his presence". By late 2001, Namangani led a force of 3,000–5,000 fighters, who trained with and fought alongside the Taliban against local and foreign anti-Taliban forces during the invasion of Afghanistan by the United States.