Israel has launched a series of strikes in Beirut, causing panic among residents in the most violent attack on the capital since the start of the war with Hezbollah.
The Israeli military said it carried out its "largest coordinated strike across Lebanon".
Israel has insisted the two-week truce in its war with Iran does not apply to Lebanon.
Lebanon's health ministry said in a preliminary toll that the strikes killed dozens of people and wounded hundreds.
"In a very serious escalation, Israeli warplanes launched a wave of simultaneous airstrikes on several Lebanese areas, resulting in, in an initial count, dozens of martyrs and hundreds of wounded," the ministry said in a statement.
The ministry reiterated its call for citizens to "reduce traffic congestion, especially in the neighbourhoods of the capital, to allow priority for rescue and ambulance services".
Lebanon's Prime Minister Nawaf Salam said the Israeli attacks hit densely populated residential areas and accused Israel of ignoring regional and international ceasefire efforts.
Lebanon's health ministry issued an emergency call for people to clear roads in Beirut for ambulances.
In a statement, the ministry said it was "urgently calling on citizens to clear the way for ambulances so they can carry out their work".
"The traffic congestion caused by the unprecedented wave of airstrikes launched by the Israeli enemy is hindering rescue efforts," it said.
Consecutive bombs shook the capital and smoke enveloped its skies. One of the strikes on a crowded neighbourhood killed at least 12 people, a security source said.
Lebanon's health ministry said hospitals were overflowing with victims.
The simultaneous strikes on the city came without warning, prompting people on streets to start running and motorists to honk their horns in an effort to clear the way, according to AFP journalists.
One of the strikes hit Corniche al-Mazraa, one of the main roads in the capital.
An AFP photographer saw widespread damage, buildings ablaze and destroyed cars.
"A plane struck, and people started running left and right, and smoke was billowing" from the targeted building, said another witness.
Israel also hit Beirut's southern suburbs and southern Lebanon, where Hezbollah holds sway, after issuing evacuation warnings for these areas, in parallel with strikes on the east.
Ambulances were heard in the targeted areas.
Read More:
Follow live updates on developments in the Middle East
US and Iran both claim victory as two-week ceasefire agreed
US-Iran truce: What we know
