The leaders of two different Iranian-backed groups, Hamas and Hezbollah, were killed in separate attacks within 24 hours of each other this week.

Hamas said its political leader, Ismail Haniyeh, was killed in an airstrike Wednesday in Tehran, where he had traveled to attend the inauguration of Iran's president. On Tuesday, senior Hezbollah commander Fuad Shukr was killed in an Israeli strike in the outskirts of Beirut.

In response to the killing of Haniyeh, Iran's supreme leader, Ayatollah Ali Khamenei, ordered a direct strike on Israel, the New York Times reported.

Hamas, the militant government Palestinians elected in Gaza, orchestrated an unprecedented attack on Israel on Oct. 7 that killed nearly 1,200 people and resulted in Israel’s military response that has killed more than 39,000, according to Palestinian health authorities. For decades, Hezbollah, a heavily armed militia group based in Lebanon, has launched rockets into Israel. Both groups are backed by Iran.

Now, fears of wider Middle East conflict are growing. The U.S. State Department released an advisory Wednesday warning Americans not to travel to Lebanon "due to rising tensions between [Hezbollah] and Israel."

Here’s what we know about what has happened in the Middle East:

The apparent assassination of Hamas political leader

Haniyeh was primarily living in Qatar, where he played a key part in the ongoing indirect Israel-Hamas ceasefire negotiations that have been brokered by Qatar, Egypt and the U.S.

Haniyeh was killed by a rocket strike in the early morning hours on Wednesday in an apparent assassination at his residence in Tehran after he attended a swearing-in ceremony for the new Iranian president, according to Hamas.

Haniyeh's funeral will be held in Qatar. Hamas's main consultative council will likely meet soon after the funeral to name a replacement, the Associated Press reported.

Hamas and Iran quickly blamed Haniyeh’s death on Israel, which had previously vowed to kill Haniyeh and other Hamas leaders in retaliation for the Oct. 7 attack.

Israel has not denied or claimed responsibility for Haniyeh’s death

As of Wednesday afternoon, Israel had not confirmed nor denied responsibility for the killing of Haniyeh.

Israeli Prime Minister Benjamin Netanyahu delivered an address to his nation Wednesday and said, “We’ll settle the score with anyone who harms us, anyone who massacres our children, anyone who murders our citizens, anyone who hurts our nation, blood is on his head.” Netanyahu did not specifically mention Haniyeh by name, however.

Israeli Defense Minister Yoav Gallant said that Israel was not trying to escalate a wider regional war, but that it was prepared for all scenarios.

Iran vows ‘harsh punishment’

Iran's Khamenei said Israel paved the way for "harsh punishment for itself," adding that it's Tehran's responsibility to avenge Haniyeh's death.

Iran's foreign ministry also condemned the White House's backing of Israel, accusing it as "as a supporter and accomplice of the Zionist regime in the continuation of the occupation and genocide of the Palestinians, in committing this heinous act of terrorism."

U.S. denies involvement in the killing of Haniyeh

White House national security spokesperson John Kirby told reporters Wednesday that the U.S. "can't confirm or verify" that Haniyeh was killed in an Israeli strike.

U.S. Secretary of State Antony Blinken said at a Wednesday event in Singapore that the United States was "not aware of or involved in" the killing of Haniyeh.

Blinken added that the focus remains on continuing to work toward reaching a ceasefire “to help end the suffering of Palestinians in Gaza” and to get the Hamas-held hostages home, which include “a number of Americans.”

Israel killed Hezbollah commander hours before Hamas political leader assassinated

Israel did claim responsibility for an airstrike that killed Hezbollah commander Shukr in Beirut on Tuesday.

That strike came after Israel blamed Hezbollah for an attack that killed 12 children and teenagers in the Israeli-controlled Golan Heights over the weekend.

Hezbollah denied responsibility for the Golan Heights attack.

The U.S. stood by Israel following the attack that killed Shukr. “What we know, in particular, is it has the right to defend itself against the terrorist organization, which is exactly what Hezbollah is,” Vice President Kamala Harris said Tuesday.

Read more: