The world is safer after Israel's killing of Hezbollah chief Sayyed Hassan Nasrallah, the top U.S. diplomat said Monday, describing the Iran-backed Lebanese group's leader as a "brutal terrorist."

"The region, the world are safer without him," Antony Blinken said, even as he insisted that "diplomacy remains the best and only path to achieving greater stability in the Middle East" and vowed the United States would continue working "urgently" to secure a ceasefire between Israel and Palestinian militant group Hamas in Gaza.

The Israeli military said on Monday its forces killed at least two leaders of a left-wing Palestinian armed group, hours after the organization said its members were hit in a strike in central Beirut.

Israeli fighter jets "struck and eliminated the terrorist" Mohammad Abdel-Aal, head of the Lebanon branch of the Popular Front for the Liberation of Palestine (PFLP), the military said in a statement.

Israeli special forces have been carrying out small, targeted raids into southern Lebanon, gathering intelligence and probing ahead of a possible broader ground incursion that could come as soon as this week, people familiar with the matter told the Wall Street Journal.

Lebanon's health ministry said an Israeli strike Monday killed six rescuers with the Hezbollah-affiliated Islamic Health Committee in the Bekaa Valley in the country's east.

An "enemy strike on the civil defense center of the Islamic Health Committee killed six emergency personnel and wounded four others" in the town of Sohmor, the ministry in a statement, condemning Israel's "targeting of rescue services".

Lebanon said Monday that an Israeli strike a day earlier near the southern city of Sidon killed 45 people, raising an earlier toll.

In a statement, the health ministry announced "45 dead and 70 wounded in an updated toll for the Israeli enemy attack on Ain al-Delb" on Sunday, while the official National News Agency said the strike targeted a building which completely collapsed.

Israeli Defense Minister Yoav Gallant on Monday strongly hinted that Israel is preparing to launch a ground offensive against Hezbollah in Lebanon.

“The elimination of (Hezbollah chief Sayyed Hassan) Nasrallah is a very important step, but it is not everything. We will use all the capabilities we have,” Gallant said to troops of the 188th Armored Brigade and Golani Infantry Brigade in northern Israel.

Caretaker Prime Minister Najib Mikati announced Monday that Lebanon is ready to implement Resolution 1701 and send the army immediately to the area south of Litani should there be a ceasefire.

“We stressed our stance on the implementation of the statement issued by the U.S. and a number of European and Arab countries that called for a ceasefire and launching discussions over the implementation of Resolution 1701, and we accept everything that was mentioned in the statement,” Mikati added.

President Joe Biden said Sunday he would speak with Israeli Prime Minister Benjamin Netanyahu, and believes that an all-out war in the Middle East must be avoided.

"It has to be," Biden told reporters as he boarded Air Force One for Washington. "We really have to avoid it."

Iran will not deploy forces to Lebanon or Gaza to confront Israel, its foreign ministry said on Monday, as Israeli strikes target its allies in the region.

"There is no need to send extra or volunteer forces of the Islamic Republic of Iran," said foreign ministry spokesman Nasser Kanani, adding that Lebanon and fighters in the Palestinian territories "have the capability and strength to defend themselves against the aggression."

In just over a week, intensified Israeli strikes in Lebanon killed seven high-ranking commanders and officials from the powerful Hezbollah militant group, including the group's leader, Sayyed Hassan Nasrallah.

The move left Lebanon and much of the Mideast in shock as Israeli officials celebrated major military and intelligence breakthroughs.