Israel's latest attack on Beirut, the capital of Lebanon, is designed to show the world its determination to eliminate anti-Israel military and political organizations in the region, an expert told CGTN on Thursday. 

"The regional situation has intensified rapidly in the past two weeks. We have seen that many security red lines have been breached," said Li Zixin, assistant research fellow at China Institute of International Studies.

"At present, parties in the region have no full trust in each other and lack strategic communication channels, which caused all parties to face extremely high risks to explore and determine new security red lines," the expert added.

Israel bombed central Beirut in the early hours of Thursday, killing at least six people, according to Lebanese health officials.

Shortly before the strike in central Beirut, three missiles also hit the southern suburb of Dahiya, where Hezbollah leader Hassan Nasrallah was killed last week, and loud explosions were heard, Lebanese security officials said. The southern suburbs came under more than a dozen Israeli strikes on Wednesday. 

Israeli forces suffered their deadliest day on the Lebanese front in a year of clashes with Hezbollah. Hezbollah said its fighters engaged Israeli forces inside Lebanon. It was the first time the movement reported ground clashes since Israeli forces pushed over the border on Monday. Hezbollah said it had destroyed three Israeli Merkava tanks with rockets near the border town of Maroun El Ras.

Israel said on Wednesday eight soldiers were killed in ground combat in south Lebanon as its forces thrust into its northern neighbor, a day after Iran fired nearly 200 missiles into Israel.

"Various black swan events may become the trigger for the outbreak of a full-scale conflict," Li warned.

The Israeli military said regular infantry and armored units joined its ground operations in Lebanon on Wednesday as Iran's missile attack and Israel's promise of retaliation raised concerns that the oil-producing Middle East could be caught up in a wider conflict.

Lebanon's Health Ministry said Israeli air raids had killed at least 46 people in the south and center of the country over the past 24 hours.

World calls for restraint

Iran said on Wednesday its missile volley, its biggest ever assault on Israel, was over barring further provocation, but Israel and the United States promised to hit back hard.

However, U.S. President Joe Biden said he would not support any Israeli strike on Iran's nuclear sites in response to its ballistic missile attack and urged Israel to act "proportionally" against its regional arch-foe.

Biden joined a call with other Group of Seven leaders to coordinate a response, including new sanctions against Tehran, the White House said.

In a statement, G7 leaders voiced "strong concern" over the Middle East crisis but said a diplomatic solution was still viable and a region-wide conflict was in no one's interest.

China called on the United Nations Security Council to take "urgent actions" to de-escalate the situation in the Middle East.

"The Security Council bears the primary responsibility for the maintenance of international peace and security," Fu Cong, China's permanent representative to the United Nations, said in remarks at a Security Council briefing on the Lebanese-Israeli situation.

Warning that the current situation is "hanging by a thread," Fu said any passive procrastination would be irresponsible, and any rhetoric of condoning further military adventurism would send a wrong message and could cause serious consequences.

1.2 million Lebanese displaced

Hezbollah said it had repelled Israeli forces near several border towns and fired rockets at military posts inside Israel.

The paramilitary group's media chief Mohammad Afif said those battles were only "the first round" and that Hezbollah had enough fighters, weapons and ammunition to push back Israel.

Israel's addition of infantry and armored troops from the 36th Division, including the Golani Brigade, the 188th Armoured Brigade and 6th Infantry Brigade, suggested that the operation might expand beyond limited commando raids. The military has said its incursion is largely aimed at destroying tunnels and other infrastructure on the border and there were no plans for a wider operation targeting Beirut to the north or major cities in the south.

Nevertheless, it issued new evacuation orders for around two dozen towns along the southern border, instructing inhabitants to head north of the Awali River, which flows east to west some 60 kilometers north of the Israeli frontier.

More than 1,900 people have been killed and over 9,000 wounded in Lebanon in almost a year of cross-border fighting, with most of the deaths occurring in the past two weeks, according to Lebanese government statistics.

Caretaker Prime Minister Najib Mikati has said about 1.2 million Lebanese had been displaced by Israeli attacks.

(With input from agencies)