At least 20 people have been killed and more than 450 wounded by a second wave of explosions from wireless communication devices in Lebanon, the country’s health ministry says.

Walkie-talkies used by the armed group Hezbollah blew up in the southern suburbs of the capital Beirut, the Bekaa Valley, and southern Lebanon - areas seen as its strongholds.

Some of the blasts took place during funerals for some of the 12 people who the ministry said were killed when Hezbollah members’ pagers exploded on Tuesday. Hezbollah blamed Israel for that attack. Israel has not commented.

The attacks came as Israel's Defence Minister Yoav Gallant announced a "new phase in the war" and as an Israeli army division was redeployed to the north.

UN Secretary General António Guterres warned of the “serious risk of a dramatic escalation” and called on all parties to “exercise maximum restraint”.

"Obviously the logic of making all these devices explode is to do it as a pre-emptive strike before a major military operation," he told reporters.

There were already rising fears of an all-out conflict after 11 months of cross-border fighting sparked by the war between Israel and Hamas in Gaza.

Hours after Wednesday’s explosions, Israel’s Prime Minister Benjamin Netanyahu vowed to return the tens of thousands of displaced people from the north of the country “securely to their homes”.

Defence Minister Yoav Gallant meanwhile said Israel was “opening a new phase in the war” and that the “centre of gravity is shifting to the north through the diversion of resources and forces”.

An army division recently engaged in Gaza has been redeployed to the north, the Israeli military confirmed.

Hezbollah says it is acting in support of Hamas - which is also backed by Iran and proscribed as a terrorist organisation by Israel and many Western countries - and will only stop its cross-border attacks once the fighting in Gaza ends.

An indication of what the group might be planning to do next could come on Thursday, when its powerful leader, Hassan Nasrallah, is due to give a speech.

Hezbollah's media office on Wednesday announced the death of 13 of its fighters, including a 16-year-old boy, since the second wave of explosions.

It also said the group targeted Israeli forces near the border and in the Israeli-occupied Golan Heights during the day, firing rockets at Israeli artillery positions.

The Israeli military said about 30 projectiles crossed from Lebanon on Wednesday, sparking a fire but causing no injuries.

It said Israeli aircraft struck Hezbollah fighters in southern Lebanon.

Wednesday's deadly explosions represent another humiliation for Hezbollah and a possible indication that its entire communication network might have been infiltrated by Israel.

Many Lebanese are still shocked - and angered - by what happened on Tuesday, when thousands of pagers exploded at the same time, after people received a message they believed had come from the group.

Twelve people - including an eight-year-old girl and an 11-year-old boy - were killed and 2,800 others were wounded by the blasts, according to the Lebanese health minister.

A BBC team was at a funeral for four of those killed in the southern Beirut suburb of Dahiya on Wednesday when they heard a loud explosion around 17:00 local time (14:00 GMT).

There was chaos and confusion among the mourners, and then reports started to come in of explosions happening in other parts of the country as well.

One unconfirmed social media video showed a man falling to the ground following a small blast during what appeared to be a Hezbollah procession attended by large crowds.

The Lebanese Red Cross said more than 30 ambulances had responded to explosions in the capital’s southern suburbs, as well as in southern Lebanon and the Bekaa Valley.

The health ministry said the deadly explosions "targeted walkie-talkies". A source close to Hezbollah also told AFP news agency that walkie-talkies used by its members had blown up.

Lebanon’s state-run National News Agency (NNA) said one man was killed when a walkie-talkie exploded inside a shop selling cellular devices in Chaat, in the northern Bekaa Valley.

It identified the device as an ICOM-V82 handheld VHF radio, which is a now-discontinued model made by the Japan-based electronics manufacturer ICOM.

NNA said another ICOM-V82 exploded at a house on the outskirts of the nearby town of Baalbek. Video footage showed fire damage to a table and wall, as well as damaged parts of what appeared to be a walkie-talkie bearing the label “ICOM”.

Photos on social media from two other locations appeared to show the same model.

Reuters news agency cited a Lebanese security source as saying the walkie-talkies were purchased by Hezbollah five months ago - around the same time as the pagers were bought.

The Axios news website cited two sources as saying that Israeli intelligence services had booby-trapped thousands of walkie-talkies before delivering them to Hezbollah as part of the group’s war-time emergency communications system.

The BBC asked ICOM's UK arm to comment on the reports, but it referred all media requests to the company's press office in Japan. The BBC has reached out to ICOM Japan.

US and Lebanese sources told the New York Times and Reuters that Israel had planted small amounts of explosives inside the pagers which blew up on Tuesday.

An ophthalmologist at one hospital in Beirut told the BBC that at least 60% of the people he had seen had lost at least one eye, with most also losing a hand.

“Probably this is the worst day of my life as a physician. I believe the number of casualties and the type of damage that has been done is humongous," Dr Elias Warrak said.

"Unfortunately, we were not able to save a lot of eyes, and unfortunately the damage is not limited to the eyes - some of them have damage in the brain in addition to any facial damage.”