Syrian government jets have bombed a rebel-held district of Homs city in the west of the country, killing several people, according to rescue workers and a monitoring group.
A pro-government media outlet said Syrian planes targeted rebels in al-Waer neighbourhood after the fighters fired at civilian areas in government-held Homs.
Al-Waer has for months been spared the intense bombardment by Syrian and Russian air forces suffered by other areas including Idlib province, controlled by President Bashar al-Assad's opponents.
The British-based Syrian Observatory for Human Rights (SOHR) said at least eight people were killed in the government bombardment.
The Syrian Civil Defence, a rescue service operating in rebel-held territory, did not give a figure, but said on its Facebook page that its centre in al-Waer was hit, wounding a staff member, and that there were fatalities elsewhere including women and children.
An opposition media activist in al-Waer, who gave his name as Osama Abu-Zeid, said that it had been months since the last significant bombardment of the area.
"Yesterday it suddenly escalated," he told Reuters news agency.
A military media unit run by Assad's Lebanese ally, Hezbollah, said the army had fired rockets and that planes had carried out three strikes against rebels in al-Waer, who it said had violated a shaky ceasefire across parts of western Syria.
The SOHR reported at least one person wounded by rockets that landed in the government-controlled Abbasiya neighbourhood in Homs.
The Syrian government has tried to conclude a deal in al-Waer that would see rebel fighters and their families evacuate the district and the government take over.
Under similar local agreements in other parts of western Syria, rebels have left with light weapons and headed mostly for Idlib.
Assad said on Wednesday that local reconciliation agreements were the "most effective way to end the war and move towards a political solution", state news agency SANA reported.
The opposition says such agreements are part of a government strategy to forcibly displace populations from opposition-held areas after years of siege and bombardment.
In September, some 120 opposition fighters and their families left al-Waer in agreement with the government, but there have been no further reports of rebels leaving the area.
The SOHR estimates several thousand rebels remain in the district.
The ceasefire brokered by Russia, which backs Assad, and Turkey, which supports rebels fighting to unseat him, took effect on December 30.
It has been fragile since the start, with the government side and rebels accusing the other of violations. The truce does not include the Islamic State of Iraq and the Levant (ISIL) group or al-Qaeda-linked fighters.
On Wednesday, shells fired by rebels into Aleppo city in northern Syria killed at least two people, SANA reported.
The Syrian Red Crescent said four of its volunteers were wounded, one critically, as they distributed aid in the Hamdaniya district.
Government forces drove rebels from their last remaining districts in Aleppo in December in a major victory for Assad. Shell fire has hit the city on several occasions since then.
Also on Wednesday, the Turkish news agency Anadolu reported that two Turkish soldiers died in a battle with ISIL, also known as ISIS, in northern Syria, citing the Turkish military.
ISIL fighters 'neutralised'
The Turkish general staff had earlier confirmed that two other Turkish soldiers had been killed and 58 ISIL fighters "neutralised" during Operation Euphrates Shield.
Turkish authorities use the word "neutralised", meaning either surrendered, captured or killed.
An operation was launched late on Tuesday to take control of Al-Bab. As a result of the operation, Free Syrian Army fighters supported by the Turkish military seized a number of strategic hills, the Turkish general staff statement said.
Operation Euphrates Shield began in late August 2016.
Source: News agencies