Captain Jeff Davis said the memorandum of understanding would likely be signed Tuesday. The measure has already been fleshed out and just needs final checking.
"We're very close, we've got a document that's just about signature-ready," Davis said.
Davis stressed the rules established with Russia are not part of a broader agreement on how the two countries could operate in Syria.
"As you know, we actually fundamentally disagree with just about everything Russia is doing in Syria, but we are seeking an MOU to narrowly focus on the issue of air-space safety," Davis said.
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Russia asked for "deconfliction" talks with the United States after Moscow began bombing Syria on September 30.
The United States is leading a 60-plus member coalition targeting Islamic State jihadists in Iraq and Syria and has been carrying out frequent raids for more than a year.
Russia also claims to be targeting IS and other "terrorists" but the Pentagon says it's hitting non-IS rebels fighting government forces loyal to President Bashar al-Assad.
So far, there have been no major incidents in the Syrian skies, though Pentagon officials said coalition planes have had to change course to avoid being in the same space as Russian jets.
Officials say the measures come down to some basic operating procedures that could possibly include which language Russian and American pilots will use for communication, the choice of radio frequency for distress calls and the altitude at which warplanes will operate.