The United States has accused Pakistan of illegally modifying the Harpoon anti-ship missile in order to expand its capability to strike at land targets, posing a security threat to the region.

This may lead to more tension between Pakistan and the United States, said a New York Times report. In this regard, the Obama administration has lodged a protest with Pakistan Prime Minister Yusuf Raza Gilani in June.
 
Pakistan bought 165 Harpoon missiles in the mid 80's to strike at land targets.

India, on the other hand, has always said Pakistan used US military aid to build-up its army against India.