The chairman of the Joint Chiefs of Staff, the top-ranking U.S. military officer, said on June 19 that the United States is working to reestablish communications with Russia's military that Moscow said it had severed after an American jet shot down a Syrian warplane.
The so-called "deconfliction" hotline in Syria has been a vital tool in protecting both sides' forces as the risk of accidental clashes has increased with both sides conducting separate campaigns in the same increasingly crowded territory.
"We will work diplomatically and militarily in the coming hours to reestablish deconfliction" and try to lower tensions, said General Joseph Dunford.
"The worst thing any of us could do right now is address this with hyperbole," he said.
Dunford said he is focused on ensuring the United States can achieve its main purpose in Syria -- the defeat of the Islamic State extremist group.
"The Russian Federation has indicated that their purpose in Syria, like ours, is to defeat ISIS, and we'll see if that's true here in the coming hours," he said.
Russia's Defense Ministry earlier said it was suspending the hotline, which it said the Pentagon failed to use before it downed a Syrian Su-22 bomber on June 18.
Despite Russia's contention, Dunford said the hotline had been used "over the last few hours."
Russia also warned on June 19 that its air-defense systems would begin tracking all U.S.-led coalition aircraft in central Syria, prompting the Pentagon to move some of its planes.
"We have taken prudent measures to reposition aircraft over Syria so as to continue targeting [Islamic State] forces while ensuring the safety of our aircrew given known threats in the battle space," Pentagon spokesman Major Adrian Rankine-Galloway said.
White House spokesman Sean Spicer said the United States is "going to do what we can to protect our interests," adding that Washington would keep an open line of communication with the Russians.
"The escalation of hostilities among the many factions that are operating in this region doesn’t help anybody," he said.
Moscow has previously threatened to scrap the deconfliction line, after an April 7 U.S. cruise missile strike on a Syrian air base in retaliation for a suspected chemical weapons attack against civilians.
But that suspension proved to be brief. The line has been a life-saving though imperfect tool since it was set up soon after Russia entered Syria's civil war in late 2015 to prop up President Bashar al-Assad.
The hotline connects U.S. military officers at an operations center in Qatar and their Russian counterparts operating in Syria.
Following the warning from Russia, Australia announced it was suspending air strikes into Syria “as a precautionary measure.”
"A decision on the resumption of ADF air operations in Syria will be made in due course," Australia's Department of Defense (ADF) said, adding its operations in neighboring Iraq would continue as part of the U.S.-led coalition fighting against the IS group.