Israel intensified its bombardment of northern Gaza and southern Lebanon on Sunday in a widening war with Iran-allied militant groups across the region, while Palestinian officials said one strike on a mosque killed at least 19 people.

A year after Hamas' October 7, 2023 attack, Israel has opened a new front in Lebanon against Hezbollah, which has traded fire with Israel along the border since the war in Gaza began. New strikes began in the Beirut suburbs late on Sunday, AP video showed.

Israel also has vowed to strike Iran after a ballistic missile attack on Israel last week.

The widening conflict risks further drawing in the United States, which has provided crucial military and diplomatic support to Israel. Iran-allied militant groups in Syria, Iraq and Yemen have joined in with long-distance strikes on Israel.

Israel is on high alert ahead of memorial events for the October 7 attack, while rallies continue around the world marking the anniversary. A stabbing and shooting attack at the central bus station in Beersheba killed a border police officer, police said. They did not identify the assailant but were treating it as a terror attack.

Israel bombards southern Beirut

Beirut's skyline lit up again late on Sunday with new airstrikes, a day after Israel's heaviest bombardment of the southern suburbs known as the Dahiyeh since it escalated its air campaign on September 23.

Israel has said it targets Hezbollah, the strongest armed force in Lebanon, which has called its firing of rockets into Israel a show of support for the Palestinians.

Lebanon's state-run National News Agency reported more than 30 strikes overnight into Sunday. Israel's military confirmed it was striking targets near Beirut and said about 130 projectiles had crossed from Lebanon into Israeli territory, with some intercepted.

"It was very difficult. All of us in Beirut could hear everything," resident Haytham Al-Darazi said. Another resident, Maxime Jawad, called it "a night of terror".

One strike killed three sisters and their aunt in the coastal village of Jiyyeh. "This is a civilian home, and the biggest evidence is those martyred are four women," said a neighbour, Ali Al Hajj. The health ministry said 25 people were killed in Israeli strikes on Saturday.

Last week, Israel launched what it called a limited ground operation into southern Lebanon after a series of attacks killed longtime Hezbollah leader Hassan Nasrallah and most of his top commanders. The fighting is the worst since Israel and Hezbollah fought a month-long war in 2006.

At least 1,400 Lebanese, including civilians, medics and Hezbollah fighters, have been killed and 1.2 million (12 lakh) driven from their homes. Israel says it aims to drive the militant group from its border so tens of thousands of Israeli citizens can return home.

The Israeli military is now setting up a forward operating base close to a UN peacekeeping mission on the border in southern Lebanon, a UN official told The Associated Press. The base puts peacekeepers at risk, said the official, who spoke on condition of anonymity due to the sensitivity of the situation.

UNIFIL, created to oversee the withdrawal of Israeli troops from southern Lebanon after Israel's 1978 invasion, refused the Israeli military's request to vacate some of its positions ahead of the ground incursion.

New evacuation orders in northern Gaza

An Israeli strike hit a mosque where displaced people sheltered near the main hospital in the central Gaza town of Deir al-Balah. Another four were killed in a strike on a school-turned-shelter near the town. The military said both strikes targeted militants. An Associated Press journalist counted the bodies at the Al-Aqsa Martyrs Hospital morgue.

Israel's military announced a new air and ground offensive in Jabaliya in northern Gaza, home to a refugee camp dating to the 1948 war surrounding Israel's creation. Israel has carried out several operations there only to see militants regroup. The military said three soldiers were severely wounded in Sunday's fighting in northern Gaza.

Israel reiterated its call for the complete evacuation of heavily-destroyed northern Gaza, where up to 300,000 people are estimated to have remained.

"We are in a new phase of the war," the military said in leaflets dropped over the area. "These areas are considered dangerous combat zones." A later statement said three projectiles were identified crossing from northern Gaza into Israeli territory, with no injuries reported.

Frantic residents fled again. "Since October 7 to the present day, this is the 12th time that I and my children, eight individuals, have been homeless and thrown into the streets and do not know where to go," said one Samia Khader.

The Civil Defence -- first responders operating under the Hamas-run government -- said it recovered three bodies, including a woman and a child, after a strike hit a home in the Shati refugee camp.

Residents mourned. Imad Alarabid said on Facebook an airstrike on his Jabaliya home killed a dozen family members, including his parents. Hassan Hamd, a freelance TV journalist whose footage had aired on Al Jazeera, was killed in shelling on his home in Jabaliya. Al Jazeera reporter Anas al-Sharif confirmed his death.

Nearly 42,000 Palestinians have been killed in Gaza since the war began, according to the Gaza Health Ministry. It does not say how many were fighters, but says a little over half were women and children.