At least 10 people died after the Bashar Assad regime shelled Syria's last opposition stronghold, Idlib Tuesday.

The attack was in violation of a deal Turkey-Russia reached last September to bring peace to the area, rescue workers and a war monitor said.

Syrian state news agency SANA said the army had carried out operations responding to "terrorist violations" of the truce in the southern part of the enclave and targeted insurgent fortifications.

Yesterday's death toll was the highest in the northwestern region for months, according to the U.K.-based Syrian Observatory for Human Rights.

Meanwhile, a Daesh suicide bomb attack targeted the headquarters of a council linked to the Hayat Tahrir al-Sham (HTS) terrorist organization in the Idlib region of northwestern Syria yesterday, killing a number of people.

The attack in Idlib city was carried out by a woman, the Syrian Observatory for Human Rights said yesterday. It targeted the headquarters of the National Salvation Government, which is linked to the HTS.

Observatory Director Rami Abdulrahman told Reuters the blast caused fatalities but did not say how many.

Turkey designated the HTS as a terrorist group in August. The HTS is the most powerful terrorist alliance in Idlib, the last major opposition-controlled enclave outside Bashar Assad's control. After the fall of Aleppo in November 2016, dozens of opposition groups, including Ahrar al-Sham and the HTS, squeezed into Idlib.

President Recep Tayyip Erdoğan and Russian President Vladimir Putin agreed in September 2018, following their talks in Sochi, to establish a demilitarized zone in Idlib to decrease tension and prevent a new conflict in the province. According to the 10-article memorandum signed between Ankara and Moscow during the meeting, the Idlib de-escalation area will be preserved, and Turkish observation posts will be fortified and continue to function. Russia will also take all the necessary measures to ensure that military operations and attacks on Idlib are avoided and the existing status quo is maintained. The agreement also envisaged the removal of "all radical terrorist groups" from the demilitarized zone by October 2019.