This agreement was affirmed and updated in February 2007 with a new treaty of friendship. Bhutan's most recent military engagements targeted Indian separatist groups operating inside Bhutan. During Operation All Clear in December 2003, Bhutanese armed forces cooperated with the Indian military in flushing out Indian militants. The Royal Bhutan Army was formed in the 1950s in response to the Chinese takeover and subsequent People's Liberation Army actions in Tibet and under intense pressure by India. In 1958, the royal government introduced a conscription system and plans for a standing army of 2,500 soldiers. The Indian government had also repeatedly urged and pressured Bhutan to end its neutrality or isolationist policy and accept Indian economic and military assistance. This was because India considered Bhutan its most vulnerable sector in its strategic defense system in regards to China. When Bhutan accepted the Indian offer, the Indian Army became responsible for the training and equipping of the RBA. The RBA established its first domestic training center at Bumthang. Around 1951, it was relocated to Lingkana and Tashichho Dzong. In 1959, another training center was established at Tencholing, which also served as the RBA general headquarters. In 1963, the Army Headquarters was moved to Dradimakhang, Thimphu. During the 1960s, the RBA established four wings, numbered as Wing 1 (Gunitsawa), Wing 2 (Changju), Wing 3 (Laya & Lingzhi), and Wing 4 (Trashigang). By 1968, the RBA consisted of 4,850 soldiers, with a recruiting goal of 600 additional soldiers a year. By 1990, the RBA was a force of 6,000 soldiers. In June 2007, the RBA stood at 9,021 active duty personnel. By 2008, this number was reduced to 8,000 active duty personnel, in line with an initiative introduced in 2005 by the Royal Government of Bhutan to reduce the strength of the RBA while increasing militia training of the Bhutanese population. The Indian Army maintains a training mission in Bhutan, known as the Indian Military Training Team (IMTRAT), responsible for the military training of RBA and RBG personnel. RBA and RBG officers are sent for training at the National Defence Academy (NDA) in Pune, and Indian Military Academy (IMA) in Dehradun. Project DANTAK of the Border Roads Organisation, a sub-division of the Indian Army Corps of Engineers, has been operating in Bhutan since May 1961.