The Turkish army hacked into Syrian military radio frequencies and warned government forces not to violate the de-escalation zone in northwest Syria’s Idlib province, the Middle East Monitor reported.

Turkey and Russia signed a deal on March 5 to halt fighting between the Turkish military and its Syrian rebel allies and Russian-backed Syrian government forces in Idlib. The deal came after a week of Turkish bombardment of Syrian troops in retaliation to an attack that left 34 Turkish soldiers dead in the province.

The ceasefire deal called for the creation of a de-escalation zone along the strategic M4 highway between areas controlled by Syrian opposition groups and those controlled the Syrian government, though both sides have reported breaches of the ceasefire.

Turkey issued a clear message to Syrian President Bashar Assad’s troops after hijacking their radio frequencies, the Middle East Monitor said.

“The leaders of your ‎army are putting your lives at risk and leading you to death when ‎they order you to bomb the de-escalation zone. Do not penetrate the de-escalation area or you will receive ‎a deadly response,” it quoted the message as saying.

The warning came as Turkish forces continued to deploy in large numbers in Idlib despite the ceasefire deal. Some 2,150 Turkish military vehicles have arrived in the province since March 5, the Syrian Observatory for Human Rights said.