"The figure we have in front of us is 280,000 people since November 27," Samer AbdelJaber, head of emergency coordination at the UN's World Food Programme (WFP), told reporters in Geneva.

"That does not include the figure of people who fled from Lebanon during the recent escalations" in fighting there, he added.

The mass displacement has happened since militants led by armed group Hayat Tahrir al-Sham (HTS) launched their lightning offensive a little more than a week ago.

That occurred just as a tenuous ceasefire in Israel's full-frontal assault on neighbouring Lebanon, following two months of Israeli escalation that drove hundreds of thousands in Lebanon to flee into Syria.

WFP warned that the fresh mass-displacement inside Syria, more than 13 years after the country's civil war erupted, was "adding to years of suffering".

AbdelJaber said the WFP and other humanitarian agencies were "trying to reach the communities wherever their needs are", and that they were working "to secure safe routes so that we can be able to move the aid and the assistance to the communities that are in need".

He also stressed the urgent need for more funding to ensure humanitarians are "ready for any scenario basically in terms of displacements that could evolve in the coming days or months".

AbdelJaber cautioned that "if the situation continues evolving (at the current) pace, we're expecting collectively around 1.5 million people that will be displaced and will be requiring our support".

*This story was edited by Ahram Online.