Russian President Vladimir Putin told Iran's top diplomat that Moscow would do everything it could to help secure peace in the Middle East, during a meeting in Saint Petersburg on Monday.

Iran's foreign minister on Monday said the Islamic republic was "stable, solid" during a meeting in Russia with President Vladimir Putin, according to Russian state TV.

Israeli Defense Minister Israel Katz warned Monday that Hezbollah's defiance would bring catastrophic consequences for Lebanon after the group's leader Naim Qassem rejected proposed direct talks between Lebanon and Israel.

The Israeli military on Monday said it had begun hitting Hezbollah positions in the Bekaa region, amid a ceasefire that began earlier this month.

"The IDF has begun to strike Hezbollah infrastructure sites in the Bekaa valley and in additional areas across southern Lebanon," it said in a brief statement on social media.

Hezbollah leader Sheikh Naim Qassem on Monday rejected Lebanon's planned direct talks with Israel, calling them a "grave sin" that will destabilize Lebanon, as he vowed to end the Israeli occupation of south Lebanon.

Qassem said Hezbollah will not give up its arms and people will return to their lands, vowing that Israeli troops will not remain on "a single inch of our occupied land".

Hezbollah has rejected Israeli Prime Minister Benjamin Netanyahu's accusation that it was jeopardizing a ceasefire and said it would keep responding to Israel's own violations and occupation of south Lebanon.

In a statement Sunday, Hezbollah said its attacks on Israeli targets in southern Lebanon and northern Israel were "a legitimate response to the enemy's persistent violations of the ceasefire since the first day of the announcement of the temporary truce".

Iranian Foreign Minister Abbas Araghchi on Monday blamed the United States for the failure of peace talks in Pakistan, after arriving in Russia for a meeting with President Vladimir Putin.

"The U.S. approaches caused the previous round of negotiations, despite progress, to fail to reach its goals because of the excessive demands," Araghchi was quoted as saying by Iranian state media.

The Israeli military said on Sunday that a soldier was killed in southern Lebanon, where a ceasefire has been in place since mid-April.

Sergeant Idan Fooks, 19, died "during combat" in south Lebanon, while "an officer and three additional soldiers were severely injured, along with a soldier who was moderately injured and a soldier who was lightly injured", the military said.

Lebanon's health ministry said Israeli strikes on the country's south on Sunday killed 14 people, the deadliest day since a ceasefire in the Israel-Hezbollah war came into force over a week ago.

It came as Israel and the Iran-backed group traded fresh accusations of breaching the fragile truce, with Prime Minister Benjamin Netanyahu saying the military was "vigorously" targeting Hezbollah and the group vowing to keep responding to "violations".

Israeli Prime Minister Benjamin Netanyahu on Sunday said Hezbollah's actions were threatening the ceasefire between Israel and Lebanon, as he pledged to "vigorously" target the Iran-backed group.

"It must be understood that Hezbollah's violations are, in practice, dismantling the ceasefire," Netanyahu said during a weekly cabinet meeting.