Hamas blames Israel for the death of a senior official in Lebanon.

Israel and the surrounding region were tense on Wednesday, a day after the killing of a top Hamas leader in Lebanon increased concerns that the war in Gaza could spill over into a wider conflict.

Hamas blamed Israel for the death of Saleh al-Arouri, the group’s top official killed since the October 7 attacks in Israel. Israeli army officials declined to comment on whether their troops were behind the explosion that killed him in a Beirut suburb. Lebanese and US officials also attributed the attack to Israel.

Mr al-Arouri was killed in the heart of a neighborhood containing the offices of Hezbollah, the powerful Lebanese militant group and ally of Hamas, likely putting pressure on the group to strike back. Hezbollah’s leader, Hassan Nasrallah, has warned that any killing in Lebanon would provoke a strong response.

Vice Admiral Daniel Hagari, the Israeli army’s chief spokesman, said in a televised briefing that the Israeli forces were “on high alert on all fronts for defensive and offensive actions.” He emphasized that Israel was “focused on fighting Hamas,” in what some Israeli analysts interpreted as a suggestion that it was not seeking a broader war with Hezbollah.

The Lebanese state news agency reported that an “enemy attack” had hit the Hamas office in the southern suburbs of Beirut, killing seven people, including Mr al-Arouri. Ismail Haniyeh, Hamas’s top political leader, said the attack killed Mr al-Arouri, two Hamas military commanders and four other members.

Najib Mikati, Lebanon’s interim prime minister, in blaming Israel for the attack, condemned what he said was an attempt to drag Lebanon into a “new phase” of the conflict.

Iran also condemned the killing. Nasser Kanaani, a spokesman for Iran’s Foreign Ministry, said the killing was the result of Israel’s “desperate and heavy defeat” during the October 7 attack and the “heroic resistance” of Hamas fighters since then. After Mr al-Arouri’s death was announced, Iranian news media published photos of Mr al-Arouri meeting Iran’s Supreme Leader Ayatollah Ali Khamenei.

Mr. al-Arouri had worked in recent years with Yahya Sinwar, the head of Hamas in Gaza, to tie the group’s military wing more closely to Iran, which regional security officials say likely helped the group develop some of its capabilities she used in battle. October 7 attack. Israel has accused Mr. Sinwar of helping plot the attack, which officials said killed about 1,200 people and abducted 240 others to Gaza.