At least two Israeli strikes hit Beirut's southern suburbs late on Monday, a security source said, with Reuters reporters seeing two flashes of light and hearing loud blasts coming from the neighbourhood.
The Israeli military had warned an hour earlier that it would strike specific buildings in the typically densely populated southern suburbs, saying armed group Hezbollah was using them as facilities and telling residents to leave.
Many residents had fled the area in recent days after a spike in Israeli strikes, but ended up sleeping in the streets of the city as shelters were full.
Fears of a ground invasion have spiked on Monday, with Lebanese troops pulling back from the border with Israel and a U.S. official saying Israeli soldiers looked set to enter Lebanon.
Reporting by Laila Bassam and Joseph Campbell in Beirut