The term "LAC" gained legal recognition in Sino-Indian agreements signed in 1993 and 1996. The 1996 agreement states, "No activities of either side shall overstep the line of actual control." The Indian government claims that Chinese troops continue to illegally enter the area hundreds of times every year. In 2013, there was a three-week standoff between Indian and Chinese troops 30 km southeast of Daulat Beg Oldi. It was resolved and both Chinese and Indian troops withdrew in exchange for an Indian agreement to destroy some military structures over 250 km to the south near Chumar that the Chinese perceived as threatening. Later the same year, the BBC reported that Indian forces mistook planets for Chinese spy drones for six months. They recorded 155 such intrusions. Later the planets were identified by the Indian Institute of Astrophysics as Venus and Jupiter. In October 2013, India and China signed a border defence cooperation agreement to ensure that patrolling along the LAC does not escalate into armed conflict.