Two key GOP senators asked Defense Secretary Leon Panetta to have his department conduct a review of security at U.S. missions around the world and suggest improvements.

Sens. Rob Portman (R-Ohio), ranking member of the Emerging Threats and Capabilities Subcommittee, and John McCain (R-Ariz.), ranking member of the Senate Armed Services Committee, wrote that they recognize the State Department is in charge of embassy security, but “we also recognize that the Defense Department plays an instrumental role in providing support to the State Department in this endeavor.”

“As investigations by the Justice Department and the State Department into the attacks in Benghazi progress, we feel it is appropriate and necessary that the Defense Department thoroughly reviews the support it provided to the U.S. mission in Libya and takes the necessary steps to ensure improvements are made where necessary to best support diplomatic security worldwide,” the senators wrote.

They asked Panetta if, prior to the Sept. 11 attack that took the lives of four Americans, whether the Pentagon conducted any security assessments in Libya and what the intelligence on Libya from DoD agencies was at the time.

“As we’ve seen in recent weeks with attacks against our embassies in Egypt, Libya, and Yemen, our diplomatic personnel are at the mercy of daily threats in hostile regions of the world, and their safety and security must be our top priority,” said Portman. “While the State Department is ultimately responsible for ensuring their protection, it’s vital that we conduct thorough oversight of the Defense Department, which plays an important role in supporting the protection of our U.S. missions overseas.”