By Steve Holland and Nandita Bose
WASHINGTON (Reuters) -President Joe Biden, his voice gripped with emotion, condemned the deadly attack against Israel by the Hamas militant group as "an act of sheer evil" and stressed U.S. support for Israelis mourning the slaughter of more than 1,000 people.
A visibly upset Biden, in remarks at the White House, voiced concern for any Americans who may be held hostage by Hamas, the Iran-backed group that launched a surprise attack on Israel from Gaza on Saturday.
At least 14 Americans died in the attack. National security adviser Jake Sullivan told reporters the U.S. believed 20 Americans were missing but that it remained unclear if they were being held hostage.
Biden said Washington will share intelligence with Israel and deploy additional experts on hostage recovery. Sullivan said no American forces would be deployed on the ground.
Biden stopped short of an overt plea to Israel to show restraint to avoid Palestinian civilian casualties in Gaza as Israel girds for a possible ground offensive against Hamas.
But he said he told Israeli Prime Minister Benjamin Netanyahu, in a phone call on Tuesday, that militants intentionally target civilians while democracies like the United States and Israel are "stronger and more secure when we act according to the rule of law."
"There are moments in this life, and I mean this literally, when the pure unadulterated evil is unleashed on this world. The people of Israel lived through one such moment this weekend," Biden told reporters at the White House.
Biden described what he called "stomach-turning" reports of "parents butchered," "babies being killed," "entire families slain" and "women raped, assaulted and paraded as trophies."
Biden said Hamas had threatened to execute hostages, including survivors of the Nazi Holocaust, in violation of "every code of human morality." He said the group's brutality and "blood thirstiness" was a reminder of the "worst rampages of ISIS."
"This is terrorism, but sadly for the Jewish people, it's not new," Biden said.
The incident had brought to the surface memories of antisemitism and the genocide of the Jewish people, he added.
In an apparent reference to Iran and Iranian-backed groups such as Lebanon's Hezbollah, Biden said he had a message for any country or organization thinking of taking advantage of the situation - "I have one word: don't."
Israel pounded the Gaza Strip on Tuesday with the fiercest air strikes in its 75-year-old conflict with the Palestinians, razing whole districts despite a threat from Hamas militants to execute a captive for each home hit without warning.
BIDEN PROMISES ISRAEL SUPPORT
Biden spoke after his third phone call in four days with Netanyahu, telling him if such an attack happened in the United States "our response would be swift, decisive and overwhelming."
Biden outlined the U.S. military assistance being sent to help Israel in its fight and said he would ask Congress to take urgent action. The White House is considering submitting a request to Congress that would include military aid to both Ukraine and Israel, said a person familiar with the matter.
The White House on Monday said it expected to fulfill additional security requests from Israel as quickly as possible. Biden promised replenishment of interceptors used by Israel's Iron Dome missile defense system as well as ammunition in addition to redoubling U.S. military presence in the region.
Biden also offered support for American Jews and said they should be allowed to worship in peace in the United States. Biden said last month that antisemitism in the United States had risen to record levels.
Israel's embassy in Washington said the death toll from Hamas' weekend attacks had surpassed 1,000, dwarfing all modern Islamist attacks on the West since the Sept. 11, 2001, attacks on the United States.