Heavy shell and rocket fire landed around the town of Ghasaniya, which is between the Turkish border and the rebel-held town of Jisr Al Shughour in Idlib province, the Observatory said.
The opposition is dissatisfied with the implementation of the deal and has yet to say whether it will attend the new talks.
A total of 25 members of Syrian regime and National Defence forces were killed, in addition to the death of 33 combatants from the People’s Protection Units, Nusra Front, an affiliate of Al-Qaeda in Syria, and other Islamist factions.
The Syrian opposition appears at odds with its Western backers over the success of the truce so far.
The fragile truce was agreed on in order to pave the way for restarting the U.N.-sponsored peace talks. Fighting continues in many parts of Syria, and rebels say the Syrian government, backed by Russian air power and fighters from Iranian-backed Hezbollah, has kept up attacks on strategically important frontlines. The situation in Syria is developing in the right direction, which creates good conditions for resuming talks between Damascus and the opposition on March 9, Farhan Haq, a deputy spokesman for the United Nations secretary general, said on Friday. In areas not covered by the truce, 552 people were killed, said the Britain-based group, which tracks the conflict via sources on the ground. The “cessation of hostilities” agreement was drawn up by Russian Federation and the United States and it excluded operations against ISIS and al-Nusra Front.
The Syrian president has refused to step down since peaceful protests in early 2011 developed into a multi-faceted war that has killed more than 270,000 people and displaced millions of people.
United Nations envoy Staffan de Mistura said the talks, originally due to begin on Monday in Geneva, would get off to a staggered start later in the week, with delegates arriving from Wednesday onwards. The U.S. State Department said on Thursday there had been no significant violations in the preceding 24 hours.
Assad said earlier this week that the militants had breached the deal from the first day and the army was refraining from responding to give the deal a chance. “If the truce ends, the regime is ready to attack in a number of areas”, said Abu Ghiath al-Shami of the Alwiyat Seif al-Sham group.
The US and its allies struck 12 Islamic State targets in Iraq and two in Syria on Friday, the US military reported on Saturday as human rights group reports civilians killed in ceasefire violations.
He said either Syrian or Russian planes carried out the strikes.
The talks will be conducted indirectly, not face-to-face.