"United Nations, May 30 (PTI) Pakistan has threatened to use nuclear weapons even if India stuck to conventional arms in any conflict, asserting that it has never subscribed to "no-first-use" of atomic weapons "
http://in.news.yahoo.com/020530/20/1p549.html
"Pakistan's refusal to institute a no-first use policy for its nuclear weapons (India has such a policy) is designed to keep Indians guessing about when Pakistan might use its nuclear weapons, preventing a major conventional attack against the inferior Pakistani army. In February, Pakistani General Khalid Kidwai, chief of Pakistan's Strategic Plans Division, which controls Pakistan's nuclear weapons, said that should India threaten to conquer a large portion of Pakistan (including Azad, Pakistan's portion of Kashmir), destroy the Pakistani army, strangle Pakistan economically, or politically destabilize Pakistan, Pakistan might use nuclear weapons"
a really good article:
http://www.cdi.org/nuclear/nuclearshadow.cfm