The White House National Security Council said Israel’s “limited operations” to destroy Hezbollah infrastructure across the border were in line with the country’s right to defend itself.

The NSC, however, warned that an expansion of that operation was a risk. It added that a diplomatic solution was the only way to achieve lasting stability along Israel’s border with Lebanon.

A Lebanese security official said Israel had conducted at least six strikes on south Beirut in the night from Monday to Tuesday, after Israel's army called on residents in the Hezbollah stronghold to evacuate.

"Six or seven Israeli strikes hit the southern Beirut suburbs," the official told AFP, requesting anonymity.

A Palestinian camp official told AFP that an Israeli strike targeted a top Palestinian militant on Tuesday in the community in the south Lebanon city of Sidon.

"The Israeli raid targeted the house of the son of Mounir Maqdah" in the Ain el-Helweh camp, the largest of Lebanon’s 12 refugee camps, the official said, requesting anonymity to discuss sensitive matters.

German airline group Lufthansa said Tuesday it had extended its suspension of flights to Beirut and Tel Aviv, citing "the current situation in the Middle East".

Flights to Beirut will now be suspended up to and including November 30, while those to Tel Aviv will be cancelled until October 31, the group said in a statement. Flights to Tehran remain cancelled until October 14. "We regret the inconvenience caused to our passengers," it added.

Caretaker prime minister Najib Mikati said Tuesday his country was facing "one of the most dangerous phases of its history", urging the United Nations to provide aid for one million people displaced by Israeli air strikes.

"Around a million of our people have been displaced because of the devastating war that Israel is waging on Lebanon," the National News Agency reported Mikati as saying. "We urgently call for more aid to reinforce our ongoing efforts to provide basic support to displaced civilians," he added in a meeting with U.N. representatives.

The Israeli military said "intense fighting" was taking place Tuesday after it launched a ground offensive against Hezbollah in southern Lebanon and warned Lebanese residents not to travel by vehicle in the region.

"Intense fighting is taking place in southern Lebanon," wrote Avichay Adraee, a spokesman for the Israeli army, in a message published in Arabic on Telegram. "For your personal safety, we ask you not to travel by vehicles from the north to the south of the Litani River" in south Lebanon.

The Israeli military on Tuesday said it had begun a "limited, localized" operation against Hezbollah targets in southern Lebanon, opening a new front in its war against the Lebanese group.

In a brief announcement, it said it was striking Hezbollah targets in areas close to the Israeli border, and that air force and artillery units were carrying out attacks to support the ground forces. It gave no details on how long the operation would last, but said the army had been training and preparing for months.

Israel is "currently conducting" limited ground operations targeting Hezbollah inside Lebanon, the U.S. State Department said Monday.

"This is what they have informed us that they are currently conducting, which are limited operations targeting Hezbollah infrastructure near the border," State Department spokesman Matthew Miller told journalists.

A Bulgarian government jet has returned to Sofia with 89 nationals who were evacuated from Lebanon.

Prime Minister Dimitar Glavchev, who welcomed them at the Sofia Airport on Monday, said the government was discussing all options for future evacuations.

Lebanon's army is repositioning troops stationed on its southern border, a Lebanese military official told AFP Monday, after the US said Israel had informed it about limited ground operations inside Lebanon.

The Lebanese army is "repositioning and regrouping forces" at the southern border following threats of an Israeli incursion against Hezbollah targets, the official said, requesting anonymity to discuss sensitive matters.