Over half of the people have been internally displaced amid ongoing hostilities in the area, said Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres.

On Saturday, the UN negotiated a six-hour humanitarian pause that enabled safe passage for more than 2,500 people to flee, he told a daily press briefing.

"The United Nations continues to pursue efforts with all parties to advocate for the protection and safe passage of all those wishing to depart from affected areas."

Over the past three days, some 39 communities were reportedly impacted by shelling in northern Hama, southern Idlib and western Aleppo governorates, while 47 communities were reportedly struck by airstrikes, he said.

"The United Nations urges all parties to ensure the protection of civilians, and to allow sustained and unhindered access by all humanitarian parties to provide life-saving assistance to all in need."

The UN Security Council on Friday failed to adopt two competing draft resolutions on the UN cross-border aid mechanism to Syrians.

The first draft prepared by Belgium, Germany and Kuwait, which seeks the re-authorization of three of the four currently mandated border crossings for 12 months, was vetoed by Russia and China. The other draft, prepared by Russia, which would authorize only two crossings for a period of six months, failed to receive the required number of votes in favor to get adopted.

Since 2014, the United Nations and aid groups have crossed into Syria from Turkey, Iraq and Jordan at four crossing points authorized by the Security Council. The mechanism expires on Jan. 10, 2020.