US Central Command spokesman Colonel Joe Buccino said Russian pilots were trying to "dogfight" a US aircraft over Syria, which he said is part of a "recent pattern of more aggressive behavior," CNN reports.

Similar attempts have taken place on more than one occasion, Buccino says.

Russian jets have violated deconfliction protocols a total of 85 times since early March, the official said, including flying too close to coalition bases.

According to Colonel Buccino, there have been about 26 cases when armed Russian planes flew over the positions of the United States and the coalition in Syria, he said.