Urgent calls grew for foreign nationals to leave Lebanon, which would be on the front line of a regional war, as Iran and its allies readied their response to high-profile killings blamed on Israel.

While diplomats worked to avert a feared conflagration, France's Emmanuel Macron and Jordan's King Abdullah II said Sunday a regional military escalation must be avoided "at all costs", the French presidency said after they held a telephone call.

Middle East tensions soared as Iran and its allies readied their response to the assassination of Hamas' political leader, blamed on Israel, spurring fears of a regional war.

Israel ally the United States said it would move warships and fighter jets to the region, while Western governments called on their citizens to leave Lebanon -- where the powerful Iran-backed Hezbollah is based -- and airlines canceled flights.

Iran's Revolutionary Guard said a short-range projectile was behind the killing of Hamas political chief Ismail Haniyeh and accused the United States of supporting the attack which it blamed on Israel, state TV reported.

The televised statement, which reiterated a call for retaliation, said a rocket with a seven-kilogram (about 15-pound) warhead was used to target the residence of Hamas' political leader in the capital Tehran on Wednesday, adding it caused heavy devastation. It didn't share details of the residence's location.

Israeli strikes early Sunday killed 12 people in Gaza, including four who were sheltering in a tent camp for displaced people inside a hospital complex, while a stabbing attack carried out by a Palestinian killed two people in a Tel Aviv suburb.

Tensions have soared following nearly 10 months of war in Gaza and the killing of two senior militants in separate strikes in Lebanon and Iran last week. Those killings brought threats of revenge from Iran and its allies and raised fears of an even more destructive regional war.

The United States will bolster its military presence in the Middle East, deploying additional warships and fighter jets to protect U.S. personnel and defend Israel amid soaring tensions in the region, the Pentagon said.

An Israeli drone strike killed five people in the occupied West Bank on Saturday, the Palestinian press agency Wafa and Palestinian sources reported, while the Israeli military said it struck a "terrorist cell" in the Tulkarem region.

France on Friday urged its nationals visiting Iran to leave immediately, after Tehran accused Israel of killing Hamas leader Ismail Haniyeh on its soil, sparking regional tensions.

"Due to the increased risk of a military escalation in the region, visiting French nationals still in Iran are invited to leave as soon as possible," the foreign ministry said.

Two days after the assassination of Hezbollah’s top military commander Fouad Shukur and Hamas chief Ismail Haniyeh, Israeli Prime Minister Benjamin Netanyahu informed international mediators that “Israel has become readier to engage in a deal over Gaza,” a media report said.

“Bring me the other party so that I talk to them over the deal!” the pro-Hezbollah al-Akhbar newspaper quoted Netanyahu as saying.

Truce negotiations between Israel and Hamas are expected to resume soon despite the assassination of Hamas chief Ismail Haniyeh in Iran, the Israeli Public Broadcasting Corporation reported on Friday.

“Haniyeh’s assassination will contribute to pushing forward the negotiations over an agreement in Gaza,” the Israeli corporation quoted unnamed sources as saying.

Turkey's communications authority blocked access to the social media platform Instagram on Friday, the latest instance of a clampdown on websites in the country.

The Information and Communication Technologies Authority, which regulates the internet, announced the decision early Friday but did not provide a reason.