Story highlights The US jets fired warning flares during the intercept

A defense official told CNN the aerial encounter lasted "several minutes."

(CNN) Two US F-22 stealth fighters intercepted two Russian aircraft Wednesday after the Russian jets crossed the Euphrates River in Syria, flying east of the "de-confliction line" that is supposed to separate Russian and US-led coalition aircraft operating over Syria, two US defense officials told CNN.

The US jets fired warning flares during the intercept of the two Russian Su-25 close air support jets according to the officials after they crossed the de-confliction line multiple times.

One of the officials said a Russian Su-35 fighter jet was also involved and that the aerial encounter lasted "several minutes."

The official said that coalition officers called their Russian counterparts about the incident via the pre-established de-confliction hotline.

US Air Forces Central Command which oversees air operations over Syria later confirmed the incident to CNN.

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