Monitoring group says at least 45 “rebel and Islamic” fighters and 32 civilians, including children, among the dead.
Dozens of residents in a besieged town outside the Syrian capital have staged a demonstration urging the United Nations to allow humanitarian aid into the area.
The protesters, mostly women and children, took to the streets on Wednesday in rebel-held Darayya, which has been encircled by President Bashar al-Assad’s troops for more than three years.
The children in the protest lined-up to form the letters “SOS”, while banners called on UN officials to help.
“[UN Humanitarian Coordinator in Syria] Mr Yacoub El Hillo, what are you doing to help us,” one banner read.
“If you can stop the shelling, you can break the siege,” another read.
No aid has entered Darayya since the beginning of its siege.
The town continued to witness heavy bombardment until a US-Russia brokered ceasefire came into force on February 27.
The opposition Media Centre in Darayya said that the reason the protest was attended mainly by women and children was to dispel the regime’s claims that the town is only inhabited by combatants.
Darayya borders a military airport used by Russian planes – which started conducting air strikes in support of Assad in late September – and the Syrian government is keen to wrest back control of the area.
The UN has said that humanitarian aid efforts in Syria have made great progress since the ceasefire went into effect.
In recent weeks, the UN and its partners have sent 536 trucks filled with aid to nearly 240,000 people, and the relief supplies have reached 18 besieged areas in the war-torn country.
El Hillo said on Wednesday that humanitarian aid will reach more besieged and hard-to-reach areas in Syria by the end of April – but made no mention of Darayya..
“We are aiming to reach 870,000 people in hard-to-reach areas, but also the specific locations in besieged areas that we have so far not been able to reach: Douma, Zamalka, Arbin, East Harasta – this is in East Ghouta – and also in Deir az Zor,” he said.
“The hope is that in the next few days, with the help of members of the task force, we will be able to complete deliveries and reach the thousands of people trapped in these places,” added El Hillo.
In addition, UN humanitarian aid is expected to reach rural areas in western Homs and the northeastern part of Aleppo.
The two-week ceasefire agreed upon by the government and opposition was expected to end on Friday.
But Staffan de Mistura, the UN special envoy for Syria, said on Wednesday that he expected the truce to continue past that date.
“From the UN point of view … there was an open-ended concept regarding the cessation of the hostilities,” de Mistura told reporters in Geneva, where UN-mediated peace talks aimed at ending the five-year-long conflict were set to resume later this week.
The High Negotiations Committee, which represents the opposition in the UN-mediated peace process, agreed to the ceasefire, but unlike other parties to the deal it consented only to a two-week pause, which ends midnight on Friday Damascus time.
On Wednesday, however, a spokesman for the committee said it would probably support a longer halt in fighting.
“If it saves more lives, let it continue,” Salem al-Meslet said.
Since the ceasefire went into effect, the Assad government and its opposition have traded accusations of violating the truce.
Rebel groups have said regime forces and their Russian allies have targeted areas where the al-Qaeda-linked al-Nusra Front and fighters of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group are not present.
ISIL and al-Nusra were not included in the ceasefire, and military operations against them have continued.
The areas where attacks are allowed against the two groups have not been publicly disclosed.