IDLIB, Syria (AP) — Syrian government forces shelled tent settlements housing families displaced by the country’s conflict in the rebel-held northwest early Sunday, killing at least 10 people and wounding dozens, opposition war monitors and first responders said.

The shelling was the latest violation of a truce reached between Russia and Turkey in March 2020 that ended a Russian-backed government offensive on Idlib province. Idlib is the last major rebel-held stronghold in Syria.

The truce has been repeatedly violated over the past two years killing and wounding scores of people.

Three top United Nations officials dealing with the Syrian crisis — Muhannad Hadi, Ayman Gharaibeh and Sudipto Mukerjee — said in a joint statement Sunday that they are “deeply concerned by today’s escalation of hostilities” in Idlib.

The statement noted that a 4-month-old baby was reportedly among those killed by the strikes. In addition to those killed and wounded, it said, some 400 people had been displaced.

The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, reported that government forces fired about 30 rockets toward rebel-held areas Sunday morning. Those areas included the Maram camp and other camps just northwest of the provincial capital of Idlib, where nine were killed and 77 wounded.

Another man was killed and several wounded in the southern countryside of Idlib while picking olives, the observatory reported.

One of the men killed in Sunday’s strikes was a refugee who had been deported by Turkish authorities two months ago, the observatory said. A Human Rights Watch report released last month found that Turkey had forcibly returned hundreds of Syrian refugees over a six-month period.

Rebel factions responded by targeting government positions with artillery and missiles in the area of Saraqib, east of Idlib, and the al-Ghab plain, the observatory reported.

The opposition’s Syrian Civil Defense, also known as White Helmets, reported that nine people were killed, including two children and a woman, and about 70 injured in shelling targeting at least six camps west of the capital. It said the dead included four children and one woman.

The pro-government Sham FM radio station said Syrian government forces shelled positions of the al-Qaida-linked Hayat Tahrir al-Sham group, the most powerful militant group in Idlib. It said Syrian and Russian warplanes also attacked the areas.

Syria’s conflict broke out in March 2011 and has since killed hundreds of thousands of people, displaced half the country’s pre-war population of 23 million and left large parts of Syria destroyed.