The United States said Monday it believed that a ceasefire was still holding in Lebanon and that it was looking at potential violations.

"The ceasefire is holding," State Department spokesman Matthew Miller told reporters after Lebanon accused Israel of violating the truce, and Israel in turn accused Lebanese militant group Hezbollah of a "serious" breach.

Israel conducted air strikes in Lebanon on Monday after vowing retaliation for an attack claimed by Hezbollah, the militant group's first since a fragile ceasefire between the two sides took effect last week.

Israeli warplanes launched strikes on the outskirts of the town of Jbaa, about 20 kilometers from the border, as well as the Deir al-Zahrani area, the National News Agency said. The Israeli army also raided Buslayya in the southern region of Iqlim al-Tuffah, Srayra in the Jezzine region, Yaroun and Berghoz, amid artillery shelling on the outskirts of Rashaya al-Fukhar and the Khiam plain.

Israeli Prime Minister Benjamin Netanyahu accused Hezbollah of a "serious violation" of the ceasefire in Lebanon on Monday after the group targeted a military position in the occupied Shebaa Farms.

"Hezbollah's firing at Har Dov (Shebaa Farms) is a serious violation of the ceasefire and Israel will respond forcefully. We are determined to uphold the ceasefire and respond to any violation by Hezbollah, no matter how minor or serious," Netanyahu said in a statement, referring to a disputed area on the Israel-Lebanon border known internationally as Shebaa Farms.

Hezbollah on Monday launched two missiles towards the occupied Shebaa Farms areas, in the first such attack by the group since the ceasefire took effect last Wednesday.

"A short while ago, the Hezbollah terrorist organization launched two projectiles toward the area of Har Dov. The projectiles fell in open areas. No injuries are reported," the Israeli army said, using Israel's term for the disputed Shebaa Farms area, where the borders of Lebanon, Syria, and Israel meet.

Caretaker Prime Minister Najib Mikati met Monday at the Grand Serail with the co-chair of the ceasefire monitoring mechanism, U.S. Major General Jasper Jeffers, in the presence of U.S. Ambassador to Lebanon Lisa Johnson.

Israeli Foreign Minister Gideon Saar rejected U.S. and French accusations on Monday that Israel was violating the terms of a truce that came into effect in Lebanon last week.

"I emphasized that Israel is not violating the ceasefire understandings but rather enforcing them in response to Hezbollah’s violations," Saar posted on X, adding that the presence of Hezbollah south of the Litani is "a fundamental violation of the agreement" and that "they must move north."

Israeli army spokesman Avichay Adraee on Monday claimed that “Hezbollah was defeated in the last battle” and Israel “must ensure that it does not smuggle weapons into Lebanon through Syrian territory.”

France's foreign minister Monday told his Israeli counterpart that all sides should respect a ceasefire started last week between Israel and Hezbollah, the French foreign ministry said.

Jean-Noel Barrot stressed to Israeli minister Gideon Saar in a phone call "the need for all sides to respect the ceasefire in Lebanon", the ministry said, after several Israeli strikes hit Lebanon since the ceasefire started Wednesday.

The Lebanese Army has decided to reinforce its current presence in south Lebanon by deploying 6,000 more troops at once in the entire area that lies south of the Litani River, a media report said.

A Lebanese Army officer was found dead inside his car after he was targeted in an Israeli strike, the Lebanese Army said on Monday.