American military and intelligence officials say they suspect that Pakistan has modified the Harpoon antiship missiles that the United States sold the country in the 1980s, a move that would be a violation of the Arms Control Export Act. Pakistan has denied the charge, saying it developed the missile itself. The United States has also accused Pakistan of modifying American-made P-3C aircraft for land-attack missions, another violation of United States law that the Obama administration has protested.

Whatever their origin, the missiles would be a significant new entry into Pakistan’s arsenal against India. They would enable Pakistan’s small navy to strike targets on land, complementing the sizable land-based missile arsenal that Pakistan has developed. That, in turn, would be likely to spur another round of an arms race with India that the United States has been trying, unsuccessfully, to halt. “The focus of our concern is that this is a potential unauthorized modification of a marit

mm it might have something to do with India developing an enormous presence in Afghanistan - traditionally an ally and safety buffer for Pakistan.
The Indians have built bases there and many more in the pipeline(no pun intended) - this will inevitably disturb Pakistan who feel they are being excluded from developements in Afghanistan, their traditional bailiwick.

Which they screwed up in the first place and exploited to harness fighters for Kashmir. What goes around comes around. Not that Indian governments are ran by saints mind you.