http://spectator.org/archives/2011/10/04/pakistan-and-china-strengtheni
As for the stationing of Chinese troops in Pakistan, it is estimated that there are currently around 11,000 soldiers of the People’s Liberation Army in Pakistan’s northern province of Gilgit-Baltistan and in Pakistani Kashmir, facilitating the opening of branches of Chinese banks and construction of concrete residential houses for these troops. This development should primarily be understood in light of the fact that engineers are working on a railroad that is intended to extend from the port of Gwadar in the southwestern province of Balochistan (a port that will be very important for future Chinese proximity to the Persian Gulf) all the way into western China.
My Comments: If the China does have a large military presence on the ground in Pakistan overseeing the construction of a rail link between Gwadur and China that could explain why their are allegations of outside interference in Balochistan.