Turkey and the United States lashed out against Syria as the death toll from a missile strike on Aleppo rose to 58, while a French photographer wounded in the conflict was confirmed dead.
"Every day a large number of innocent children and women fall dead in Syria," Turkey's Prime Minister Recep Tayyip Erdogan said on Sunday during a visit to the United Arab Emirates.
"We will not remain silent on those committing crimes against their people.... We will not remain silent on the brutal dictator in Syria," Erdogan, a key backer of Syria's opposition, added.
Turkey's southern neighbour has been locked in a 23-month-long conflict in which the United Nations estimates more than 70,000 people have been killed.
On Sunday alone, according to a toll compiled by the Syrian Observatory for Human Rights, at least 105 people were killed in violence across the country.
Early in the revolt against President Bashar al-Assad's regime, Turkey broke ties with Damascus and led international calls for his ouster.
Ankara has since backed the uprising against Assad by offering shelter to defectors from Assad's army and hosting opposition meetings. About 200,000 Syrian refugees have fled to Turkey, many of them living in squalid camps.
Erdogan's statement came as the French foreign ministry confirmed that freelance photographer Olivier Voisin, who was seriously wounded in Syria on Thursday, died of his wounds after surgery in Turkey.
In Paris, a foreign ministry spokeswoman confirmed that Voisin, 38, had died, after he suffered head and arm injuries from shrapnel when a shell exploded near the northwest Syrian province of Idlib.
His pictures have been published in major French and British newspapers and he collaborated with AFP in January, providing about a dozen pictures from Aleppo.
His death takes the number of reporters who have perished in Syria to at least 21, according to a count by AFP and Paris-based media watchdog Reporters Without Borders.
"France once again pays homage to the work of journalists who risk their lives for freedom of expression," French Prime Minister Jean-Marc Ayrault said in a statement.
The Observatory, a Britain-based monitoring group, updated its death toll from a missile attack on Friday on the northern city of Aleppo, saying it killed at least 58 people, among them 36 children.
On Sunday the army used tanks to shell the Tariq al-Bab district in eastern Aleppo city, the Observatory added.
Also Sunday, a senior US official urged the Syrian opposition to rethink its decision to pull out of an international meeting in Rome on Thursday, which the new US Secretary of State, John Kerry, will attend.
"We are stressing... that they have an opportunity in Rome, to see the countries that have been their greatest supporters and to present to all of us how they see the situation on the ground in security, humanitarian, political and economic terms," said the official.
Already Saturday Washington had condemned the Assad regime "in the strongest possible terms" for Friday's strike, which activists say was carried out using surface-to-surface missiles.
The attack was the latest demonstration "of the Syrian regime's ruthlessness and its lack of compassion for the Syrian people it claims to represent", said State Department spokeswoman Victoria Nuland.
She repeated Washington's call for Assad to step down.
Activists reported the death in a war-torn district of southern Damascus of a prominent Syrian comedian, Yassin Bakush, killed in the Assali district after his car was hit by a shell.
The jihadist Al-Nusra Front claimed responsibility for a suicide attack on an army factory earlier this month in the central city of Hama that left at least 60 people dead.
And in northern Syria on Sunday, rebels closed in on a police academy in the town of Khan al-Assal in Aleppo province, as warplanes bombarded their positions there, the Observatory said.
The rebels already have large swathes of northern Syria under their control, chiefly Idlib province to the northwest, Raqa and Hasake east of Aleppo.