Valparaíso (Chile) (AFP) - US Secretary of State John Kerry warned Monday that a Russian warplane's "incursion" into the air space of Washington's NATO ally Turkey risked provoking a serious escalation.

"We're greatly concerned about it because it is precisely the kind of thing that had Turkey responded under its rights could have resulted in a shoot-down," he said, at a public event in Chile.

Kerry said he had talked with Turkish Foreign Minister Feridun Sinirlioglu and had consulted senior colleagues and would push Russia to communicate more clearly about its operations.

"It is precisely the kind of thing that we warned against," he said, referring to the Pentagon's attempts to set up a so-called "de-confliction" mechanism with Russian commanders.

"And it is why we have engaged in initial conversations with Russia about making certain there's no possibility of accidental conflict," he said, speaking in Chile's Congress.

"Those conversations are even more intense now and we will see very quickly if this can be defused," he added.