On March 26, 1971, Bangladesh declared its independence from Pakistan. According to this TOI piece first published on Nov 6, 2011 and reproduced below, declassified top-secret US documents revealed how India resisted pressure despite US's hostile stand against it
After they ousted the Soviets and overthrew the pro-communist regime in Kabul, the mujahideen and the ISI needed a new destination, a new Islamic war — it was the unrest in the Valley that they set their sights on