The volatile Middle East, already grappling with Israel's brutal war on Gaza, resembles a tinderbox after Wednesday's twin explosions in Iran and the Beirut drone strikes a day earlier.

The blasts killed at least 103 people, wounded 200 more, ripping through a crowd of mourners commemorating slain Revolutionary Guards general Qassem Soleimani on the fourth anniversary of his killing in a United States drone strike.

No group claimed responsibility for the blasts which, according to AFP archives, were the country's deadliest attack since a 1978 arson that killed at least 377 people.

State-run TV labeled the blasts a "terrorist attack." They came with regional tensions already soaring a day after the Beirut strike which killed Hamas No. 2 Saleh al-Arouri.

A U.S. official confirmed Wednesday that "an Israeli strike" took the life of al-Arouri, the most high-profile figure killed during the nearly three months of Israel's war has wrecked havoc on the Gaza Strip.

Following Tuesday's unclaimed Beirut attack, Israeli army spokesman Daniel Hagari said the military was "highly prepared for any scenario."

He did not comment directly on the killing of al-Arouri, who Hamas said will be buried on Thursday in Beirut's Shatila Palestinian refugee camp.

Israel and Iran have long been bitter enemies. Violence involving Iran-backed groups in Lebanon, Iraq, Syria and Yemen has spiked during the Gaza war sparked by the unprecedented Oct. 7 Hamas incursion that killed around 1,140 people.

There have been repeated, deadly exchanges of fire across the Lebanon-Israel border, attacks on shipping in the Red Sea area vital for global trade, and strikes against U.S.-led coalition forces in Iraq and Syria.

More intense wider warfare has so far been avoided, but the Iran blasts rattled global markets, sending oil prices up by more than 3%.

Following the al-Arouri killing, Germany warned its citizens to leave Lebanon quickly and said, "further deterioration of the situation and expansion of the conflict cannot be ruled out."

Cross-border fire

In its bloodiest-ever war on Gaza, Israel has launched a relentless bombardment and ground invasion has killed at least 22,313 Palestinians, mostly women and children, and reduced swathes of Gaza to rubble.

The United Nations estimates 1.9 million Gazans are displaced, and the World Health Organization (WHO) has warned of the risk of famine and disease, with only a minimal amount of aid entering.

After Tuesday's killing of al-Arouri, Lebanon's Iran-backed armed group Hezbollah blamed its foe Israel for the strike in its Shiite Muslim stronghold of southern Beirut.

Although Israel did not claim the assassination, Hamas and Lebanese security sources accused it of killing al-Arouri, 57, a founder of the Hamas military wing.

Hezbollah vowed the killing of al-Arouri and six other Hamas members would not go unpunished, labeling it "a serious assault on Lebanon ... and a dangerous development."

Hezbollah leader Hassan Nasrallah warned Israel against all-out war on the country to its north. But in a televised speech he also said Israel has sent "messages" that it was "settling scores" with Hamas leaders and did not intend to target Lebanon or Hezbollah.

During the Israel-Hamas war, including on Thursday, Israel has traded regular cross-border fire with armed groups, mainly Hamas ally Hezbollah.

Iran's Foreign Minister Hossein Amirabdollahian said the Beirut strike proved Israel "has not achieved any of its goals."

Just a few hours after those remarks, blasts in Soleimani's hometown of Kerman, Iran, tore through crowds gathered to honor Soleimani, the commander killed in a 2020 Baghdad drone strike by Israel's top ally the U.S.

Soleimani headed the Quds Force, the foreign operations arm of Iran's Islamic Revolutionary Guard Corps, setting Iran's political and military agenda across the region.

Iran declared Thursday a day of mourning. Supreme leader Ayatollah Ali Khamenei blamed "evil and criminal enemies of the Iranian nation" and said: "This disaster will have a harsh response, God willing."

Following the blasts, President Ebrahim Raisi canceled a Thursday visit to Türkiye.

Saudi Arabia, which last year reconciled with Iran after a seven-year diplomatic rupture, expressed "sincere condolences, sympathy and solidarity with Iran in this painful event."

Washington also expressed sympathy "to the victims and their loved ones," while calling "ridiculous" any suggestion of U.S. involvement.

"We have no reason to believe that Israel was involved in this explosion," State Department spokesperson Matthew Miller added.

Israeli military spokesman Hagari did not comment when asked about the Iran blasts. "We are ready on all fronts," he said.

'Settling the score'

Israel has vowed to kill commanders of the Hamas movement. The head of Mossad, David Barnea, said Israel's spy agency "is committed to settling the score with the murderers" who carried out the Oct. 7, and with Hamas's leadership.

European Union foreign policy chief Josep Borrell warned the strike that killed al-Arouri was "an additional factor that can cause an escalation of the conflict."

In the Israeli-occupied West Bank, the Palestinian territory where al-Arouri was born, the Palestinian Authority called a general strike to mourn his death.

During the Israel-Hamas war violence in the West Bank has surged to levels unseen in nearly two decades, with at least 321 Palestinians killed by Israeli troops or settlers, the Palestinian Health Ministry said.

At a protest in Ramallah on Wednesday against al-Arouri's killing, one resident, Hala Abu Gharbiyeh, said his death will not affect "the resistance."

"These people carry messages of eternal freedom until the occupation is defeated. The message cannot stop with the martyrdom of the leader," she said, holding a Palestinian flag.

In Israel's northern coastal city of Nahariya, near the border with Lebanon, many people are carrying weapons. Residents said they fear al-Arouri's killing could spark war in their region.

"We're scared," said Lee Zorviv, a clothing store owner.