Hundreds of Syrian militants have launched attacks against regime forces in several parts of Syrias Idlib province, killing up to 40 Syrian soldiers, the Russian Defense Ministry said on Thursday. The militants had seized two settlements in one of the offensives, the ministry said, saying Syrian army troops had been forced to abandon some of their positions in the southeast of the so-called Idlib de-escalation zone under rocket fire. Idlib is the last opposition-held swathe of territory in the country and hundreds of thousands of people in the area have fled in recent weeks amid heavy air strikes by Russian and Syrian forces. Russia said Syrian regime forces had killed up to 50 militants and wounded up to 90 attackers. The attacks began on Wednesday, it said, saying some fighting was still going on. About 40 soldiers had been killed and up to 80 wounded. Moscow said the attackers were from different groups, including Hayat Tahrir al-Sham that were equipped with pickup trucks, armored personnel carriers, tanks and heavy machine guns. UN Special Envoy to Syria Geir Pedersen will visit Russia on Friday, according to Russia’s Foreign Ministry. Pedersen is scheduled to hold talks with Foreign Minister Sergei Lavrov and Defense Minister Sergei Shoigu. Diplomatic sources suggested that discussions will likely focus on the work of the Constitutional Committee and the evolving situation in Syria’s northwest. Although Moscow hasn’t previously announced details of the visit, a Russian Foreign Ministry source told Sputnik news agency that Lavrov’s agenda includes holding a round of talks with Pedersen on Friday. Spokesperson for the Office of the UN Special Envoy for Syria Jenifer Fenton pointed out that Pederson’s visit comes in line with talks held by him before briefing the Security Council on Jan. 29. Lavrov had announced that the formation and activation of the Constitutional Committee was the most prominent outcome in Syria during 2019. Priority is on advancing the work of the Committee, he stressed, indicating that the issue is on the agenda of his talks with the UN envoy and the influential parties. Talks are expected to focus on the humanitarian situation in Syria, especially after Moscow succeeded in confirming its view on extending the international mechanism for humanitarian aid for six months.