Hezbollah said its fighters were still battling Israeli troops near south Lebanon's Beaufort castle on Monday, a day after Israel said it seized the strategic fortress and troops raised the Israeli flag there.

The European Union on Monday urged Israel to halt its military operation in Lebanon, after Israel seized the strategic Beaufort Castle and said it would resume strikes on southern Beirut.

"We call on Israel to stop its military escalation in Lebanon and to respect Lebanon's sovereignty and territorial integrity," EU spokesman Anouar El Anouni said.

Iranian Foreign Minister Abbas Araghchi said Monday that attacking Lebanon violates the ceasefire "on all fronts," warning that "the U.S. and Israel are responsible for the consequences of any violation," after Israeli officials threatened to bomb Beirut's southern suburbs.

"The ceasefire between Iran and the US is unequivocally a ceasefire on all fronts, including in Lebanon. Its violation on one front is a violation of the ceasefire on all fronts. The US and Israel are responsible for the consequences of any violation," Araghchi wrote on X.

France's President Emmanuel Macron said on Monday he had encouraged his US counterpart Donald Trump to pursue his "determined efforts" to reach a ceasefire deal with Iran to end the Middle East war.

Israel's defense minister said Monday there would be "no calm in Beirut" if Hezbollah attacks continued and vowed to establish a military-controlled zone in the area of south Lebanon's Litani River.

"The Dahieh in Beirut is no different from the communities in northern Israel -- if there is no calm in the north, there will be no calm in Beirut," Israel Katz said in a statement released by his office, referring to the Beirut southern suburb and Hezbollah stronghold where he had earlier Monday ordered strikes.

The U.N. Security Council is set to hold an emergency meeting Monday on the fighting in Lebanon after Israel's military took over the medieval castle of Beaufort in Lebanese territory, diplomatic sources told AFP.

Israeli Prime Minister Benjamin Netanyahu has vowed to push deeper into Lebanon and called Sunday's operation a "dramatic shift" in the campaign against Hezbollah.

The United States and Iran said Monday they had again traded strikes, straining an already fragile ceasefire as negotiations between the two sides have stalled.

Weeks of complicated talks marked by sharp rhetoric and occasional flare-ups of violence have not managed to reach a deal to end the war and reopen the Strait of Hormuz, which is essential to oil supplies.

The Israeli army announced that one of its soldiers had been killed on Monday in fighting in southern Lebanon, bringing to 26 the number of Israeli military deaths since early March.

Staff Sergeant Adam Tzarfati, 20, "fell in combat in southern Lebanon", the army said in a brief statement.

President Joseph Aoun said Monday that Lebanon was facing "a vicious and reprehensible Israeli aggression", after Israel stepped up its offensive against Hezbollah with the capture of the medieval Beaufort Castle.

Aoun condemned the Israeli offensive in a post on X and pledged to "work to end the suffering of the Lebanese people, and people in the south in particular".

Iran's chief negotiator warned the United States is not to be trusted Sunday, saying Tehran would not agree to any deal with Washington unless it fully secures Iranian rights.