MOSCOW (Reuters) – Russian air strikes that accidentally killed three Turkish soldiers in Syria were launched based on coordinates provided to Russia by the Turkish military, Kremlin spokesman Dmitry Peskov said on Friday.

The Turkish military has said the “friendly fire” incident occurred during an operation against Islamic State, highlighting the risk of unintended clashes between the numerous outside powers in a complex war.

“Unfortunately, our military, while carrying out strikes on terrorists, was guided by coordinates given to them by our Turkish partners, and Turkish servicemen should not have been present on those coordinates,” Peskov, the Kremlin spokesman, told a conference call with reporters.

“It was a lack of coordination in providing coordinates, that is how I would formulate it,” said Peskov.

Speaking with reporters in the city of Afyon, Turkish Deputy Prime Minister Numan Kurtulmus said it was important that President Vladimir Putin had expressed his condolences to his Turkish counterpart Tayyip Erdogan.

“From our side the issue is being investigated. Initial information shows this was an accident … and an undesired incident as a result of incorrect information, coordinates,” Kurtulmus said in televised comments.

“It has been understood that closer coordination is required, both with the coalition and with Russia.”

(Reporting by Christian Lowe in Moscow and Humeyra Pamuk in Istanbul; Editing by Andrew Osborn)