BEIRUT: Syrian opposition groups allied with Turkey lobbed hundreds of missiles and artillery rockets at government posts in northwestern Syria on Tuesday, in retaliation for a deadly attack that killed dozens of their fighters a day earlier.

The renewed violence has undermined an already shaky ceasefire in place since March that aimed to quell military operations and government troop advances in the overcrowded rebel-held enclave.

The escalation also comes as relations between Russia and Turkey, who negotiated the ceasefire, show signs of strain over Ankara’s increased military involvement in a region stretching from Syria to the Caucasus and the Mediterranean. Russia is a main supporter of Syrian President Bashar Assad’s government.

UN Special Envoy for Syria Geir Pederson appealed to Russia and Turkey to contain the situation. Meanwhile, Turkish Foreign Minister Mevlut Cavusoglu and his Russian counterpart, Sergey Lavrov, discussed the attack in Idlib as well as the situation in Nagorno-Karabakh and Libya in a telephone call on Tuesday, the Turkish Foreign Ministry said. It did not provide details.

Monday’s strike was the deadliest in Idlib since the Turkish-Russian-brokered truce there came into effect, raising fears that the truce could further fray. Some 1 million people were displaced by the last offensive inside the already packed enclave, home to over 3 million.

In retaliation, the Turkey-backed groups, operating under the umbrella of the National Front for Liberation, fired hundreds of artillery rounds and missiles since late Monday at government posts in territories adjacent to areas they control in Idlib and Aleppo provinces.

A spokesman for the NFL, Naji al-Mustafa, said the rebels’ military retaliation targeted and killed Russian officers in southern Idlib, as well as Syrian soldiers working in the area.

The report could not be independently verified and there was no immediate comment from Russia or Syria.

The Britain-based Syrian Observatory for Human Rights recorded hundreds of projectiles lobbed by opposition fighters at nearly 30 government posts in different locations in southern Idlib, western Aleppo and the coastal province of Latakia.

Published in Dawn, October 28th, 2020