"We continue to have contacts with our Pakistani counterparts, and we continue to emphasize the importance of resolving this case," State Department spokesman P J Crowley told reporters.
Clinton raised this matter during her telephonic conversation with Zardari last week and also when she met Kayani on the sidelines of the Munich conference over the weekend, Crowley said.
"The phone call with President Zardari was largely about this issue," he said.
"We continue to express to them the importance of resolving this. We continue to express to them the fact that our US diplomat has diplomatic immunity and should be released," he said, adding that by not releasing its diplomat Pakistan is violating the Vienna Convention.
"We continue to make clear to the Government of Pakistan that our diplomat has diplomatic immunity, in our view was acting in self-defence, and should be released. Pakistan should fulfill its international obligations under the Vienna Convention. (US) Ambassador (to Pakistan) Munter met today with President Zardari to continue to make that point," Crowley said.