Pentagon officials do not know what secrets the Iraqi government may be telling Moscow, after Iraqi leaders unexpectedly entered into an intelligence-sharing agreement with Russia this weekend.

The Defense Department’s second-in-command told the Senate on Tuesday the agreement came as a surprise to military intelligence and Pentagon teams are scrambling to make sure classified intelligence from the U.S. does not make its way into the hands of Russian, Syrian or Iranian authorities.

Over the weekend, the Iraqi military’s Joint Operations Command announced that it would enter into an intelligence sharing agreement “about ISIS terrorism” with Syria, Russia and Iran. Exactly what sort of information Iraq agreed to share with Russia, or has shared already, was a matter of some confusion during Tuesday’s Senate Armed Services Committee hearing. Deputy Defense Secretary Bob Work acknowledged that the Defense Department doesn’t have a firm handle on the sort of communications going on between the Iraqi government and Moscow.

“We were caught by surprise that Iraq entered into this agreement with Syria, Iran and Russia. Obviously, we are not going to share intelligence with either Syria, or Russia, or Iran. So we are in the process of working to try and find out exactly what Iraq has said. Certainly we are not going to provide any classified information that would help those actors on the battlefield.” Work said in response to a question from Sen. Joni Ernst, R-Iowa.

Director of National Intelligence James Clapper said Russia was in Syria primarily to bolster President Bashar al-Assad’s regime. Russian President Vladimir Putin’s claims this week that his forces were in Syria to defeat the Islamic State was, Clapper said, “a belated motivation.”

Clapper suggested that mutual mistrust between the parties could limit the scope of the Iraq’s intelligence sharing agreement. “As far as the joint intelligence arrangement is concerned. Can’t go into detail here in this forum … But each of the parties entering into this are a little bit suspicious of just what is entailed here. We will have to see how robust a capability that actually provides.”

U.S. Cyber Command commander and NSA chief Adm. Michael Rogers identified Russia as probably the most capable adversary the United States faces online. The recent breach of the Joint Staff civilian email system, for instance, has been attributed to a Russian affiliated group and affected as many as 4,000 email accounts.

In fiscal 2015, Congress appropriated more than $1.6 billion in train and equip funding for the Iraqi military, including trucks and small arms but also some potentially sensitive pieces of equipment related to improvised explosive device detection. Detailed information about how U.S. troops detect mines and explosive devices on the battlefield could represent a vulnerability for the United States if that equipment were to fall into the wrong hands. And then there are the people, more than 3,550 U.S. troops are in Iraq right now officially serving in train and assist roles. But that’s not all they do. In May, a U.S. Special Forces raid resulted in the death of Abu Sayyaf, an ISIS senior leader in Syria.

The administration’s focus right now is trying to “deconflict” the battlefield in Iraq and Syria, to ensure that Russia, the United States, Syria and Iran don’t collide in the fog of war. “That was the primary purpose of the discussion between President Obama and President Putin yesterday. If you are going to act on this battlefield, we have to deconflict,” Work said. Convincing Russia to pursue a broad political solution rather than a narrow military one, remained a key goal, however an unlikely one.

“They would like to do a military-first [approach in Syria], followed by a political transition. We believe those two things have to go in parallel. That has been our consistent message,” Work said.