Lebanon's health ministry on Tuesday said 13 people, including a child, were killed in an Israeli strike near a south Beirut hospital the previous night, revising upwards its initial toll of four.
Another 57 people were wounded in the strike near the Rafik Hariri Hospital, Lebanon's biggest public health facility, located a few kilometres from the city centre, the health ministry said.
The facility in the Jnah neighbourhood sustained minor damage in the strike, which flattened four buildings in its vicinity, said an AFP correspondent in the area.
Rescuers were still searching for survivors beneath the rubble on Tuesday, said the correspondent who heard a cell phone ringing under chunks of concrete.
The strike on Monday night came as Israel targeted Beirut's southern suburbs with heavy strikes following evacuation warnings.
The Ouzai neighbourhood, minutes away from Jnah, was hit for the first time during the conflict, Lebanon's official National News Agency (NNA) reported.
There was no warning, however, for the area around the Rafik Hariri Hospital, which is densely-populated and has seen an influx of people displaced from areas further south.
Nearly a month of all-out war between Israel and Hezbollah has killed at least 1,489 people in Lebanon, according to an AFP tally of Lebanese health ministry figures.
It has displaced more than a million people, according to Lebanese authorities, with thousands crossing the border to neighbouring Syria.
The strikes on Ouzai and Jnah triggered an exodus of residents, piling more pressure on shelters struggling to accomodate the displaced.