Russia’s Defence Ministry was cited by the RIA news agency on Friday as saying that the Turkish troops had been hit by artillery fire from Syrian government forces who were trying to repel an offensive by rebel forces.

It was quoted as saying that Ankara had failed to notify Moscow of the presence of Turkish troops in the area hit by shelling despite being in regular communication with the Russian military.

The Turkish troops had been deployed directly alongside anti-government rebels, the ministry was cited as saying. But according to information provided by Turkey there were no Turkish troops in the area and Russia said that Turkish forces «shouldn’t have been there.»

Russian war planes did not carry out any airstrikes in the area at the time of the incident and Moscow did everything it could to help once it learnt of the Turkish troop presence, the ministry was cited as saying.

That included ensuring Syrian forces stopped shelling to allow Turkey to evacuate its dead and wounded.

Meanwhile, two Russian frigates carrying cruise missiles have been deployed to Syria, Russian navy officials said. Admiral Makarov and Admiral Grigorovich of the Black Sea Fleet are currently en route to the Syrian coast with Kalibr cruise missiles on board. Both warships previously took part in Russia’s offensive in Syria.

NATO ambassadors to meet at Turkey’s request

Turkey has sent thousands of troops and heavy military hardware into Syria and President Recep Tayyip Erdogan has warned that Ankara will launch a full-scale offensive to repel Syrian forces unless they pull back from Turkish observation posts in the region.

Though trying to coordinate their efforts on Syria, Russia backs Syrian President Bashar al-Assad, while Turkey backs rebel forces opposing Assad.

Responding to Thursday’s killings, a senior Turkish official said on Friday that Ankara would no longer stop Syrian refugees from reaching Europe. Turkey blamed an air strike by Syrian government forces for the deaths.