An Israel Defense Forces (IDF) armored officer was killed on Thursday in southern Lebanon by an explosive drone launched by Hezbollah, the IDF said in a statement.

Israel's state-owned Kan TV News reported that the officer was killed after a Hezbollah militant fired the drone at a tank of Israeli forces operating in southern Lebanon, north of the Litani River.

Earlier in the day, Lebanon's National News Agency reported that at least nine people were killed and dozens of others injured in Israeli strikes on Thursday targeting southern Lebanon and the Bekaa Valley in the east of the country.

The developments came despite Israel and Lebanon agreeing on Wednesday to implement a ceasefire following trilateral negotiations in Washington.

With the Israel-Lebanon conflict continuing despite a ceasefire agreement, Iran's Islamic Revolution Guard Corps (IRGC) said on Thursday that Israel must immediately stop its attacks against the Lebanese people and withdraw from occupied Lebanese territories.

In a statement on its official outlet Sepah News, the IRGC reaffirmed that Iran's primary condition for accepting the April 8 truce with the United States and Israel was a comprehensive ceasefire on all fronts, including Lebanon.

UN chief condemns killing of UN peacekeeper in Lebanon

UN Secretary-General Antonio Guterres on Thursday condemned the killing of a UN peacekeeper in southern Lebanon and urged all parties to respect the cessation of hostilities agreement.

Sgt. Milovan Jovanovic, a Serbian peacekeeper serving with the UN Interim Force in Lebanon (UNIFIL), was killed on Wednesday when a mortar struck a UN position near Marjayoun in southern Lebanon, according to a statement by UN spokesperson Stephane Dujarric.

Two other peacekeepers were wounded in the incident and are receiving treatment at a UNIFIL medical facility. An investigation is underway, the statement said.

Seven UNIFIL peacekeepers have been killed since hostilities escalated in Lebanon on March 2 following the Israeli-US war on Iran.

"Attacks on peacekeepers must stop. They are grave violations of international humanitarian law and of Security Council Resolution 1701 (2006) and may amount to war crimes," the statement said.

(With input from Xinhua)