Regime shelling killed seven civilians in Syria's jihadist-controlled Idlib region on Thursday, in the latest violence to threaten a seven-month-old truce, a war monitor said.
Rocket fire targeted a village and an adjacent camp for the internally displaced in Idlib's southeastern countryside, according to the Britain-based Syrian Observatory for Human Rights.
Two women and three children were among the seven civilians killed, the monitor said.
Another 30 people were wounded, it said.
Regime ally Russia and rebel-backer Turkey in September inked a buffer zone deal to prevent a massive regime offensive on the Idlib region, near the Turkish border.
But the region of some three million people has come under increasing bombardment since former Al-Qaeda affiliate Hayat Tahrir al-Sham took full control of it in January.
The UN has expressed concern over escalating violence, warning that the flare-up is threatening aid deliveries to some 2.7 million people in need.
More than 86,500 people fled their homes in February and March as a result of the surge in violence, it said.
Iran, Russia and Turkey are set to discuss the Idlib deal during a fresh round of talks on April 25-26 in Kazakhstan.
Delegations from the Syrian regime and armed opposition groups are also expected to participate, according to the Kazakh foreign ministry.
Iran's Foreign Minister Mohammad Javad Zarif this week visited Damascus and met Turkish President Recep Tayyip Erdogan in Ankara.
The trio of foreign brokers have taken the diplomatic lead through the so-called "Astana process" that has largely sidelined UN diplomacy since its launch in January 2017.
Syria's war has killed more than 370,000 people and displaced millions since the conflict began with the repression of anti-government protests in 2011.