ANKARA, Turkey (AP) — Turkey’s foreign minister said Tuesday that Ankara and Moscow were trying to keep peace efforts for Syria alive despite Syrian government advances and a deadly clash between Turkish and Syrian forces.

However, Mevlut Cavusoglu also renewed a call on Russia to “rein in” the Syrian government forces and reiterated Turkey’s determination to retaliate against any future Syrian attack on its troops.

On Monday, Turkish artillery targeted Syrian government forces in northern Idlib province, responding to shelling that killed seven Turkish soldiers and a Turkish civilian. A Syrian war monitor said 13 Syrian troops were also killed in the clash.

The exchange of fire in Idlib, the last rebel stronghold in Syria, increased tensions between the two neighboring countries and threatened to drive a wedge between Russia and Turkey, which have sought to coordinate their actions in Syria.

“The Astana and Sochi peace processes have not been completely destroyed but have lately started to suffer and to lose importance,” Cavusoglu told reporters in Ankara, referring to Russian-Turkish peace initiatives that have also involved Iran.

He added that Turkish officials were in constant contact with Russian counterparts in order “to keep the Astana and Sochi processes alive, to strengthen them, and to arrive at a political solution.”

The assault on the Turkish troops came amid a Syrian government offensive that has been advancing since December into the country’s last rebel stronghold, which spans Idlib province and parts of the nearby Aleppo region. Turkish troops are deployed in some of those rebel-held areas to monitor an earlier cease-fire that has since collapsed.

Cavusoglu, who held a telephone conversation with Russian Foreign Minister Sergey Lavrov hours after the incident, added: “The regime’s aggressiveness has to be stopped immediately. That was the message I gave Lavrov yesterday.”

Cavusoglu dismissed claims by Russia that it cannot fully control the Syrian government and said the attack came despite a prior notification by Turkey of its troops’ coordinates in Idlib. Russia insisted that Turkey had failed to notify the Russian military about troop movements overnight.

Meanwhile, funerals were being held across Turkey for the Turkish servicemen that were killed.

The deaths were one of the highest single-day tolls for Turkish troops in Syria. Ankara has lost scores of military personnel in the Syrian war.