Washington (CNN) US officials said they were "deeply concerned" after Turkey carried out a series of airstrikes Tuesday against US allies fighting ISIS in Syria and Iraq.

A senior US defense official told CNN that the US was given about one hour's advance notice of the strikes by the Turkish military. The official added that no US or coalition advisers were in the vicinity.

Turkish warplanes struck targets in northern Syria and the area of Sinjar in northern Iraq. The Turkish armed forces issued a statement saying it had "neutralized" 70 PKK "terrorist" fighters -- 40 in northern Iraq and 30 others in northeastern Syria.

The Turkish government has been conducting a decades-long fight against the PKK, a Kurdish separatist group that has carried out terrorist attacks in Turkey.

But Kurdish elements of the Syrian Democratic Forces, America's primary Syrian ally in the fight against ISIS, and the Iraq-based Kurdish Peshmerga both said that they suffered casualties as well as a result of the airstrikes.

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