"The number of people who have crossed into Syria from Lebanon fleeing Israeli airstrikes — Lebanese and Syrian nationals — has reached 100,000. The outflow continues," Filippo Grandi wrote on X.
"UNHCR (UN Refugee Agency) is present at four crossing points alongside local authorities and @SYRedCrescent to support new arrivals," Grandi added.
Since Sept. 23, Israel has launched massive airstrikes against what it calls Hezbollah targets across Lebanon, killing more than 900 people and injuring over 2,700 others, according to the Lebanese Health Ministry.
Several Hezbollah commanders were killed in the assault, including its leader Hassan Nasrallah, who was assassinated in an airstrike in Beirut on Friday.
Hezbollah and Israel have been engaged in cross-border warfare since the start of Israel's war on Gaza, which has killed nearly 41,600 people, mostly women and children, following a cross-border attack by the Palestinian group Hamas on Oct. 7 last year.
The international community has warned that Israeli attacks in Lebanon could escalate the Gaza conflict into a wider regional war.