Israel's foes vowed revenge on Saturday after Iran-backed Lebanese militant group Hezbollah announced its longtime leader Hassan Nasrallah was killed in an Israeli air strike on Beirut suburbs.
World powers also warned of the killing's potential repercussions, with the specter of all-out war looming over the Middle East.
Iran
First Vice President Mohammad Reza Aref warned Israel that Nasrallah's death would "bring about their destruction", Iran's ISNA news agency quoted him as saying.
The foreign ministry of Iran, which finances and arms Hezbollah, said Nasrallah's work will continue after his death. "His sacred goal will be realized in the liberation of Quds (Jerusalem), God willing," foreign ministry spokesman Nasser Kanani posted on X.
Supreme leader Ayatollah Ali Khamenei announced five days of public mourning.
Russia
Russia's foreign ministry said "We decisively condemn the latest political murder carried out by Israel" and urged it to "immediately cease military action" in Lebanon.
Israel would "bear full responsibility" for the "tragic" consequences the killing could bring to the region, the ministry added in a statement.
Germany
Foreign Minister Annalena Baerbock told ARD television that the killing "threatens destabilization for the whole of Lebanon", which "is in no way in Israel's security interest".
United Nations
UN chief Antonio Guterres said he was "gravely concerned by the dramatic escalation of events in Beirut in the last 24 hours".
Hamas
Palestinian militant group Hamas, whose unprecedented October 7 attack on Israel sparked the devastating war in Gaza that drew in fellow Iran-backed groups including Hezbollah, called Nasrallah's killing "a cowardly terrorist act".
"We condemn in the strongest terms this barbaric Zionist aggression and targeting of residential buildings," Hamas said in a statement.
Palestinian Authority
Palestinian president Mahmud Abbas offered his "deep condolences" to Lebanon for the deaths of Nasrallah and civilians, who "fell as a result of the brutal Israeli aggression", according to a statement from his office.
Iraq
Prime Minister Mohammed Shia al-Sudani condemned in a statement Israel's "shameful attack", calling it "a crime that shows the Zionist entity has crossed all the red lines".
Syria
Israel "confirms through this despicable aggression, once again... its barbarism and wanton disregard for all international standards and laws", said a Syrian foreign ministry statement carried by state news agency SANA.
Huthis
The Iran-backed Yemeni rebels, who have been firing on ships in the Red Sea in solidarity with Hamas, said in a statement that "the martyrdom of Hassan Nasrallah will increase the flame of sacrifice, the heat of enthusiasm, the strength of resolve" against Israel.
Turkey
President Recep Tayyip Erdogan, whose country maintains diplomatic relations with Israel but who has been a sharp critic of its offensive in Gaza, said on X that Lebanon was being subjected to a "genocide", without referring directly to Nasrallah.
US Republicans
Leading Republicans in the House of Representatives welcomed the end of a "reign of bloodshed, oppression, and terror" by "one of the most brutal terrorists on the planet".
"Justice was delivered for Israeli victims of his heinous crimes, their families, and the United States," while President Joe Biden's administration should stop calling for a ceasefire and its diplomatic pressure on Israel, they added in a statement.