The Syrian Observatory for Human Rights estimates that 120 people were killed in the war-torn country on Monday.
Fighting raged across many cities as some UN observers left Damascus at the end of their four month mission.
Activists say government forces launched air strikes south of capital, killing dozens of people.
Amateur footage, which euronews cannot independently verify, is said to have been shot in Aleppo, the same city where a Japanese journalist was killed, during clashes in an eastern suburb.
Three other reporters are missing, according to British-based activists.
At least 18,000 people have now died since the uprising against President Bashar al-Assad began 17 months ago.
The last of the UN observers are due to leave Syria by Friday following the expiration of their mandate at the weekend. They will leave behind a small liaison office in Damascus in the hope of a political solution.
While tens of thousands of refugees have already fled the conflict in Syria, attention is now turning to the estimated one million people who have been displaced within the country, many taking refuge in local schools.
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