"This is something that we take very seriously. We have raised the issue with the Pakistani government. The (Pak) government has responded with an agreement in principle for mutually agreed inspections," the assistant secretary of state for public affairs P J Crowley, said.
"In this particular case, we have some concerns. We shared them with the government of Pakistan. The government of Pakistan has been responsive," Crowley said.
The US has also accused Pakistan of modifying American-made P-3C aircraft for land-attack missions. Both are violations of the US law, including the Arms Control Export Act.
"When we have concerns about how those systems should be used, we raise these concerns with the appropriate governments," he noted.
Earlier on Aug 30, The New York Times news report said that the US has accused Pakistan of illegally modifications in the Harpoon anti-ship missile to expand its capacity to strike land targets, a potential threat to India.