Concerned that U.S. and Russian fighter jets might inadvertently get too close for comfort over Syria, high-ranking defense officials from both nations met by secure teleconference Thursday afternoon to discuss how best to de-conflict the non-cooperative air campaigns.

Moscow on Wednesday unleashed Russian forces that had been building strength in Syria for weeks in support of the beleaguered and war-weary regime of Bashar al-Assad and at least notionally in an effort to bring more force to bear against Islamic State militants (ISIL).

Acting Assistant Secretary of Defense for International and Security Affairs Elissa Slotkin spoke to her Russian counterpart Thursday afternoon, about 24 hours after Secretary of Defense Ashton Carter announced the “deconfliction” talks would commence within days. Slotkin emphasized to the Russians Carter’s earlier point that any offensive action in Syria should be focused on defeating ISIL, Pentagon spokesman Peter Cook said during a press conference on Thursday.

“The U.S. provided an initial proposal to enhance safety, prevent miscalculation and avoid actions, activities or operations that could escalate tensions,” Cook said. “The Russians outlined some of their own ideas. Both sides agreed to consider the proposals and provide feedback in the coming days.”

“She made clear the priority should be taking steps to ensure the safety of aircrews operating over Syria,” Cook added.

Some suggested safety checks were encouraging pilots from both countries to observe rules “for safety of flight,” “ensure navigation through professional airmenship including use of appropriate and active communications and avoid actions that could cause unnecessary confrontation,” Cool said. He later admitted that the two countries have not even decided in what language pilot-to-pilot communication should be conducted.

Russia launched several airstrikes within Syria on Wednesday, which U.S. officials, including Carter and a U.S. military spokesman on the ground in Iraq have said were on anti-regime forces not aligned with ISIL. That prompted a phone call between Carter and his Russian counterpart, Defense Minister Sergey Shoygu to begin talks on how to avoid clashing with Russia over Syria. Carter told Shoygu he hoped Russia would join the fight against ISIL but not with the parallel motive of propping up the Assad regime.

“Defeating ISIL without pursuing parallel political transition only risks escalating the civil war in Syria and with it, the very extremism and instability that Moscow claims to be concerned about and aspires to fight,” Carter said during a press conference at the Pentagon on Wednesday. “That approach…is tantamount to pouring gasoline on the fire.”

The U.S. position that a lasting defeat of ISIL must include the removal of Assad from office, has not changed, Carter said. Both sides agreed to share information that will ensure the safety of military pilots, but are not sharing targeting information or intelligence data, he said. 

Carter also insisted that Russia’s presence on the ground and in the air in Syria will in no way affect U.S. and coalition anti-ISIL operations in that country or in Iraq. However, in the 24 hours since Russia began its bombing campaign, just one of 22 airstrikes was in Syria.

Col. Steve Warren, spokesman for Operation Inherent Resolve, was piped in from Iraq to the Pentagon on Thursday to report on the situation on the ground. By the numbers, he said the 60-nation coalition as of Thursday has conducted a total 7,184 airstrikes in Iraq and Syria.

At least 15,000 personnel have been trained, including Kurdish Peshmerga fighters, Iraqi soldiers and Syria rebel forces, Warren said. There are a total 5,451 coalition troops on the ground in Iraq, including 3,359 U.S. personnel. Together, 30 percent of the ground ISIL held at its operational peak has been reclaimed, Warren said.

The train-and-recruit program for Syrian rebel forces is “paused” for now as U.S. officials take stock of its efficacy. Though U.S. forces continue to recruit and train moderate Syrian rebels, they are no longer being sent back into Syria, Warren said.

Carter has testified before Congress that the U.S. military has a responsibility to provide air support and other aid for Syrian rebels it trains. That policy is complicated by evidence Russia is striking non-ISIL targets in Syria. Cook refused to say whether the U.S. would strike Russian forces if U.S. trained rebels came under their fire, but said the policy stands. He also said that during the half dozen or so Russian strikes conducted so far, “we don’t believe they hit ISIL targets.”

Warren also doubled down on Carter’s statement that U.S. operations would not change because of the Russian presence in Syria.

“While there is always danger of inadvertent contact …we are continuing with our operations and as the  deconflicting continues, we will factor that into our operations,’ he said.