Hamas gunmen killed at least 600 Israelis, injured over 1,800 and took 100 hostages in a surprise assault, marking the deadliest day in Israel since the Yom Kippur war 50 years ago. As a U.S. interdenominational group condemned the Palestinian assault and Christian leaders called for prayers, Israel's retaliation strikes have killed over 300 Gazans.

In an unparalleled assault that caught Israel unprepared on Simchat Torah, a significant Jewish holiday, Hamas militants from the Gaza Strip launched a multi-pronged attack at dawn on Saturday. The group fired thousands of rockets and deployed fighters who breached Israel's fortified borders by air, land and sea.

In a statement to The Christian Post, Robert J. Pacienza, senior pastor of Coral Ridge Presbyterian Church and founder of the Institute for Faith & Culture, said:

"The violent attacks on Israel necessitate an urgent call to all Americans to pray for the state of Israel and the people in the region. These events have been perpetrated by terrorists and resourced by the terrorist state of Iran. Democracy and principled freedom in Israel, throughout the Middle East, and the world are at risk because of these efforts.

"Christians in particular should be concerned for the humanitarian rights and religious liberties that will be threatened as a result. Considering the biblical duty of peace and honor, and the principles of just war, we have a responsibility to speak out on behalf of those that are being unjustly assaulted."

The BBC reported on Sunday that Palestinian officials say Israeli airstrikes have killed at least 313 people in the Gaza Strip, with almost 2,000 wounded.

In an interview with Sky News on Sunday, Tzipi Hotovely, Israel's ambassador to the U.K., said their focus is on rescuing the hostages, some of whom are "young children" and "people with dementia."

"Our first aim is, first of all, to bring back those people that have been taken hostage," she said. "We're talking [about] over 100 people that are hostage at the moment in [the] Gaza Strip and Israeli families don't know where they are.

"I've seen the horrible photos and videos coming from people being taken to Gaza and this is our duty to our people," Hotovely added.

Soon after the Hamas attacks on Israeli civilians were reported on Saturday, the interdenominational group Congress of Christian Leaders called for prayers for Israel's peace and security.

The Rev. Johnnie Moore wrote on Twitter that his group is "issuing an emergency call to prayer for the peace and security of Israel." Churches from all over the world will gather this weekend standing with Israel and dedicating time to pray for Israel, he added.

Sacha Roytman Dratwa, CEO of the Combat Antisemitism Movement, condemned the "coordinated terrorist assault on Israel" in a statement, saying it "shocks the conscience."

Roytman Dratwa called on "leaders across the globe to be swift and unequivocal in condemning the evil actions of Palestinian terrorist groups, including the barbaric murder of Israeli women and children inside their own homes on a Shabbat morning."

He continued, "There is only one moral choice at this perilous moment — to stand resolutely with the brave soldiers of the Israel Defense Forces and the resilient people of Israel as they wage a just war to defend themselves from bloody-thirsty killers whose hatred of Jews has no bounds."

He added, "May the memories of the victims of today's heinous violence forever be a blessing, and we pray for the full and speedy recovery of the wounded."

In Sderot, near Gaza, bodies of Israeli civilians lay in the streets. Shlomi, a resident, described a "sea of bodies" to Reuters. Israelis recounted their experiences on live TV and social media while barricaded in safe rooms or detained by Hamas inside their homes.

Footage showed Israelis running for their lives during an overnight rave near Gaza. "I said, 'OK, I'm going to die, it's OK, just breathe, just close your eyes,'" Gili Yoskovich told the BBC.

Esther Borochov survived an attack on a dance rave by playing dead. "I couldn't move my legs," she told the newswire. Senior military officers were among the Israeli casualties, according to the Israeli military.

By early Sunday, Israeli troops were still engaged with Hamas fighters in southern Israel. An Israeli army spokesperson stated the situation was not fully under control.

Hamas leader Ismail Haniyeh warned that the assault would extend to the West Bank and Jerusalem. Haniyeh cited threats to Jerusalem's Al-Aqsa Mosque and the ongoing Gaza blockade as motivations, the newswire said.

Israeli Prime Minister Benjamin Netanyahu declared Israel is "at war" after Hamas launched the attack Saturday morning. "We will take mighty vengeance for this wicked day."

The Israeli cabinet approved measures to cripple Hamas and Islamic Jihad, including cutting essential supplies to Gaza. In Gaza, hospitals struggled with a surge of casualties.

Streets in Gaza were deserted, except for racing ambulances. Israel cut power to the area, plunging it into darkness.

In Gaza, residents rushed to buy supplies. Some evacuated their homes for shelters. Scores of Palestinians were killed attempting to cross into Israel, according to Reuters.

Hamas claimed to have captured dozens of Israelis, including soldiers. Israel's military confirmed hostages were taken. The Associated Press reported seeing four hostages taken from Kfar Azza, including two women.

Saleh al-Arouri, Hamas deputy chief, told Al Jazeera that they had enough hostages to force Israel to free all Palestinians in its jails.

U.S. President Joe Biden expressed support for Israel. "The world is watching," he warned nations hostile to Israel. A senior Biden official said the U.S. was working to contain the crisis in Gaza.

Demonstrations supporting Hamas erupted across the Middle East. The attack was praised by Iran and Hezbollah.

Hamas cited escalated Israeli attacks on Palestinians as the reason for their assault. "This is the day of the greatest battle to end the last occupation on Earth," Hamas military commander Mohammed Deif was quoted as saying.

Tensions had been rising in Gaza, but neither side was expected to escalate.

Israelis criticized their security forces for not responding more quickly. Footage on Hamas channels showed captured or killed Israeli soldiers.