This picture taken from the West Bank city of Hebron shows projectiles above the Israeli city of Ashdod on October 1, 2024. Hazem Bader, AFPPARIS, France -- World leaders called on Iran and Israel to step back from the brink after Tehran fired a barrage of rockets at its arch-rival.

Tehran said Tuesday's attack -- launched as Israel said it was mounting a ground offensive against Iran-backed Hezbollah in Lebanon -- was in response to the killings of Iran-backed militant leaders.

READ: Israel vows response as Iran fires missile barrage

- World powers should calm region: China -

"The Chinese side calls on the international community, especially major influential powers, to truly play a constructive role and prevent the situation from further deteriorating," said a foreign ministry spokesman in a statement published online.

- Restraint on all sides: Moscow -

"This situation is developing by the most worrying scenario," Kremlin spokesman Dmitry Peskov said Wednesday.

"We call all sides towards restraint ... and we condemn any acts that could lead to the death of the civilian population."

Hours earlier, Russia's foreign ministry spokeswoman Maria Zakharova denounced what she said was the "complete failure" of US President Joe Biden's approach.

"The White House's incomprehensible statements demonstrate its complete helplessness in resolving crises," she posted on Telegram.

- Pope calls for day of prayer -

Pope Francis called for a day of prayer for peace on October 7, the anniversary of Hamas' attack on Israel.

- 'Totally unacceptable': US -

Biden ordered the US military to "aid Israel's defense against Iranian attacks and shoot down missiles that are targeting Israel".

US Secretary of State Antony Blinken said the attack was "totally unacceptable".

"Initial reports suggest that Israel, with the active support of the United States and other partners, effectively defeated this attack," Blinken said.

- 'Need a ceasefire': UN -

United Nations Secretary-General Antonio Guterres condemned the "broadening conflict in the Middle East".

With Israel's conflict with Hezbollah broadening alongside its ongoing war with Palestinian Hamas militants in Gaza, Guterres slammed "escalation after escalation" in the region.

"This must stop. We absolutely need a ceasefire."

- Israel vows retaliation -

Israel vowed to retaliate in the wake of Iran's attack.

"This attack will have consequences. We have plans, and we will operate at the place and time we decide," said Israeli military spokesman Rear Admiral Daniel Hagari.

On Wednesday, it declared Guterres "persona non grata", banning the UN chief from entering the country for failing to condemn Iran's missile attack on Israel.

- 'Heroic rocket launches': Hamas -

Hamas said the attack was retaliation for killings including Hezbollah chief Hassan Nasrallah in Beirut and Hamas leader Ismail Haniyeh in Tehran.

Hamas "blesses the heroic rocket launches carried out by the Islamic Revolutionary Guard Corps in Iran against wide areas of our occupied lands," adding it was "in revenge for the blood of our heroic martyrs".

- 'Restraint': Spain -

Spanish Prime Minister Pedro Sanchez condemned the Iranian strikes and called for an end to the "spiral of violence" blighting the Middle East.

Foreign Minister Jose Manuel Albares said Madrid was issuing "a new call to all the actors, obviously including Israel, to show restraint and not escalation".

- 'Strongest' terms: France -

French President Emmanuel Macron condemned Iran's attacks against Israel "in the strongest possible terms", adding that France had "mobilized" its military resources in the Middle East to counter Tehran.

Macron also demanded that "Hezbollah cease its terrorist actions against Israel and its population", while asking Israel to "put an end to their military operations as soon as possible".

- 'Steadfast commitment': Britain -

British Prime Minister Keir Starmer condemned Iran's attack "in the strongest terms".

During a call with his Israeli counterpart Benjamin Netanyahu, Starmer also "expressed the UK's steadfast commitment to Israeli security and the protection of civilians."

- 'Defuse the situation': Japan -

Japan's new Prime Minister Shigeru Ishiba said missile attacks by Iran on Israel were "unacceptable".

"We will condemn this strongly. But at the same time, we would like to cooperate (with the United States) to defuse the situation and prevent it from escalating into a full-on war," he said.

© Agence France-Presse