The window for a political solution between Turkey and Russia over Syria’s Idlib is narrowing as the Syrian regime forces’ push to capture the country’s last rebel-held stronghold has left 13 Turks dead in seven days.

Turkey, meanwhile, is determined to keep its troops on the ground at any cost, even after the Feb. 10 attack by the Syrian regime that killed five Turkish soldiers and wounded five others.

Forces loyal to Syrian President Bashar al-Assad, backed by close air support from Russian and Syrian fighter jets, continue their advances toward Idlib’s city center through the strategic town of Saraqeb, which fell under regime control last week. Pressing from the north, pro-Iranian militias are also heading toward the province from western Aleppo.

Turkey, for its part, is steadily increasing boots on the ground. As of Feb. 10, it has dispatched an excess of 100 military convoys to the area. In its bid to fortify ​Idlib’s defenses from the south and eastern fronts, this marks Turkey’s largest military buildup in the area since 2011. Currently, the number of Turkish soldiers in the area has reached some 9,000, with one armored brigade, two mechanized infantry brigades and a special forces team equipped with several howitzers and rocket launchers.