Back the bold part with some documentary evidence.
Some other documented evidence in the form of a timeline:
1963 - 1987: Rise of Kashmiri Nationalism
1963-1964: On 27 December, mass upsurge occurs in Kashmir Valley when the holy relic is found missing from the Hazratbal Shrine; the lost relic is recovered on 4 Jan 1964. Protest demonstrations occur in Kashmir Valley and Pakistan held parts of the State in December against Articles 356 and 357 of the Indian Constitution being extended to the state, by virtue of which the Center can assume the government of the State and exercise its legislative powers. The special status accorded to the State under Article 370, continues to get eroded over years[19]
1965: Indo-Pakistani War of 1965: Pakistan takes advantage of the discontent in the Valley and sends in a few thousand armed Pakistani infiltrators across the cease-fire line in August in Operation Gibraltar, and incidents of violence increase in Kashmir Valley; A full Indo-Pakistani war breaks out which ends in a ceasefire on 23 September.
1966: In January, Tashkent Declaration is signed by both countries agreeing to revert to pre-1965 position, under Russian mediation. Pakistan supported guerrilla groups in Kashmir increase their activities after the ceasefire. Kashmiri nationalists Amanullah Khan and Maqbool Bhat form another Plebiscite Front with an armed wing called the Jammu and Kashmir National Liberation Front(NLF) in Azad Kashmir, with the objective of freeing Kashmir from Indian occupation.[20]
1972: Republic of India and Pakistan agree to respect the cease-fire as Line of Control. India and Pakistan sign the Simla Agreement in July, which has a clause that the final settlement of Kashmir will be decided bilaterally in the future and that both the sides shall respect the LOC.
1976: Maqbool Bhat is arrested on his return to the Valley. Amanullah Khan moves to England and NLF becomes Jammu and Kashmir Liberation Front(JKLF).
1979: The USSR invades Afghanistan. The US and Pakistan are involved in training, recruiting, arming, and unleashing the Mujahedin on Afghanistan.[21]The mujahedin so recruited would take on their own agenda of establishing Islamic rule in Kashmir from the late 1980's.
April 13, 1984: The Indian Army takes Siachen Glacier region of Kashmir. Maqbool Bhat is executed.
Timeline of the Kashmir conflict - Wikipedia, the free encyclopedia