The United States has "unequivocally" condemned attacks by "Hamas terrorists", after the Palestinian Islamist group launched its biggest attack on Israel in years.
At least 200 Israelis have been killed in the attack and more than 1,100 wounded as gunfire rages into the night.
"The United States unequivocally condemns the unprovoked attacks by Hamas terrorists against Israeli civilians," National Security Council spokeswoman Adrienne Watson said in a statement, adding that "there is never any justification for terrorism."
National Security Advisor Jake Sullivan has spoken to Israeli National Security Advisor Tzachi Hanegbi and will remain in close contact with Israeli partners over the operation, according to the statement.
"We stand firmly with the Government and people of Israel and extend our condolences for the Israeli lives lost in these attacks," Ms Watson added.
Taoiseach Leo Varadkar described the firing of rockets by Hamas as "appalling".
The United Nation's High Commissioner for Human Rights has called for an immediate halt to violence in Gaza.
Volker Tuerk said he was shocked by reports that hundreds of rockets had been fired towards Israel and reports that Israeli civilians have been taken hostage.
"This attack is having a horrific impact on Israeli civilians," Mr Tuerk said in a statement. "Civilians must never be the target of attack."
He called on Israel to take precautions to avoid civilian casualties as it responded to the attacks with air strikes into Gaza.
"I call for an immediate stop to the violence, and appeal to all sides and key countries in the region to de-escalate to avoid further bloodshed," Mr Tuerk said.
The European Union has "unequivocally" condemned the attacks by Hamas and called for an immediate stop to the violence.
"We follow with anguish the news coming from #Israel. We unequivocally condemn the attacks by Hamas.
"This horrific violence must stop immediately. Terrorism and violence solve nothing. The EU expresses its solidarity with Israel in these difficult moments," EU foreign policy chief Josep Borrell said.
European Council president Charles Michel also condemned the "indiscriminate attacks launched against Israel and its people this morning inflicting terror and violence against innocent citizens".
"My thoughts are with all the victims. EU stands in solidarity with Israeli people in this horrific moment."
Zelensky says Israel has 'indisputable' right to defence
Ukrainian President Volodymyr Zelensky, whose country is fending off a Russian invasion, said that Israel had an unquestionable right to defend itself from attacks from Palestinian militants.
"Israel's right to defence is indisputable," Mr Zelensky said on Telegram.
"Terror is always a crime, not just against one country or specific victims, but against humanity as a whole," he said.
"The world must stand united... so that terror does not attempt to take or destroy life anywhere and at any moment," Mr Zelensky added.
A special department has been set up to help Ukrainians who may need assistance in Israel, according to his statement.
British Prime Minister Rishi Sunak said Israel has an "absolute right to defend itself".
In a post on X, he wrote: "I am shocked by this morning's attacks by Hamas terrorists against Israeli citizens.
"Israel has an absolute right to defend itself.
"We're in contact with Israeli authorities, and British nationals in Israel should follow travel advice."
I am shocked by this morning's attacks by Hamas terrorists against Israeli citizens.
— Rishi Sunak (@RishiSunak) October 7, 2023
Israel has an absolute right to defend itself.
We're in contact with Israeli authorities, and British nationals in Israel should follow travel advice.
Germany's foreign minister said Israel has its "full solidarity".
Germany "firmly condemns the terrorist attacks from Gaza against Israel", Foreign Minister Annalena Baerbock said.
Israel "has our full solidarity" and "the right, guaranteed by international law, to defend itself against terrorism", Ms Baerbock said on social media.
The UK unequivocally condemns the horrific attacks by Hamas on Israeli civilians.
— James Cleverly🇬🇧 (@JamesCleverly) October 7, 2023
The UK will always support Israel's right to defend itself.
Britain's Foreign Minister James Cleverly said the UK unequivocally condemns the "horrific attacks" by Hamas on Israel.
He said the UK will always support Israel's right to defend itself.
French President Emmanuel Macron also condemned the attacks against Israel, and said he had discussed the situation with Mr Netanyahu.
"I have spoken to President Herzog and Prime Minister Netanyahu. I condemn the attacks carried out from Gaza on Israel, its soldiers and its people," he wrote on social media platform X, previously known as Twitter.
"France stands in solidarity with Israel and the Israelis, committed to their security and their right to defend themselves," Macron added.
Mr Macron in an earlier social media post had condemned the" terrorist attacks" against Israel.
Egypt warned of "grave consequences" from an escalation in tensions between Israel and the Palestinians in a statement from the foreign ministry carried by the state news agency.
It called for "exercising maximum restraint and avoiding exposing civilians to further danger".
Meanwhile, Italy said it backed "Israel's right to defend itself" against the "brutal attack" by Hamas.
The government said it "condemns in the strongest terms the terror and the violence under way against innocent civilians", adding: "We back the right of Israel to defend itself".
Ukraine also expressed solidarity with Israel after a barrage of rockets was fired from Gaza.
"Ukraine strongly condemns the ongoing terrorist attacks against Israel, including rocket attacks against the civilian population in Jerusalem and Tel Aviv. We express our support for Israel in its right to defend itself and its people," the Ukrainian foreign ministry said on social media.
Spain expressed shock over the "indiscriminate violence" of the barrage of rocket fire and attacks launched by Hamas.
"We strongly condemn the extremely serious terrorist attacks from Gaza against Israel. We are shocked by this indiscriminate violence," Foreign Minister Jose Manuel Albares wrote on X.
