The United States and Russia have signed a memorandum of understanding that establishes measures so their pilots steer clear of each other as they conduct separate bombing campaigns in Syria, the Pentagon said Tuesday.
Pentagon press secretary Peter Cook said the document was signed earlier in the day and took immediate effect.
"There's a series of protocols in place that effectively are intended to avoid any sort of risk of a mid-air incident between our air crews and Russian air crews," Cook said.
"If they follow these protocols, we should not have the risk of engagement with Russian air crews over Syria."
Moscow also reported that both countries had signed the memorandum.
The Pentagon says Russia had initially asked for "deconfliction" talks with the United States after Moscow launched its air war in Syria on September 30 in support of President Bashar al-Assad's forces.
US defense officials were furious after they only got a vague "heads-up" from Moscow about an hour before Russia began its bombing campaign.
Cook said the memorandum establishes several protocols aimed at maintaining professional airmanship, as well as the use of radio frequencies and the creation of a secondary line of communication on the ground.
However, he was quick to stress that the understanding did not signal broader agreement with Russia's Syria strategy.
"The MOU does not establish zones of cooperation, intelligence-sharing or any sharing of target information in Syria." he said.
"We continue to believe that Russia's strategy in Syria is counter-productive and their support for the Assad regime will only make Syria's civil war worse."
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 is hitting non-IS rebels fighting forces loyal to Assad.
Earlier Tuesday, a CNN report said Russian planes had twice in the last two weeks flown very close to coalition planes -- within 500 feet in one instance.
"The Russians need to abide by these flight safety protocols that they have now agreed to because we don't want miscalculations or misunderstanding," Cook said when asked about the report.