Israeli strikes late on Tuesday targeted Lebanon's three northern border crossings with Syria for the first time, Lebanon's transport minister Ali Hamieh told Reuters.
The strikes came moments after US President Joe Biden announced that a ceasefire would come into effect at 4:00 a.m. local time (0200 GMT) on Wednesday to halt hostilities between Lebanese armed group Hezbollah and Israel.
Hamieh said it was not immediately clear whether the roads had been cut off as a result of the strikes. Israeli raids on Lebanon's eastern crossings in recent weeks had already sealed off those routes into Syria.
Syria's Red Crescent said a volunteer was killed and another was injured in "the aggression that targeted Al-Dabousyeh and Al-Arida crossings ... as they were performing their humanitarian duty of rescuing the wounded early on Wednesday."
The strike damaged several ambulances and work points, it added in a statement.
Multiple casualties reported
Syrian state TV reported 18 people were injured, some in critical condition, in an Israeli strike on the Arida border crossing, with the wounded transported to nearby hospitals, while casualties were also reported in a separate Israeli strike on the Dabousieh border crossing with Lebanon.
The Israeli military did not immediately comment. It has previously stated that it targets what it says are Iran-linked sites in Syria as part of a broader campaign to curb the influence of Iran and its ally Hezbollah in the region.
Separately, US Central Command (CENTCOM) said later on Tuesday that it struck an Iranian-aligned militia weapons storage facility in Syria in response to an Iranian-aligned attack against US forces in the country on Monday.
Later on Wednesday, Syrian state media claimed that six people had been killed in an attack on a border crossing in the country's Homs area.