'Isis-level savagery' by Hamas killed 11 Americans, says US

At least 11 Americans have been killed in Israel after Hamas militants launched an attack on the country, US President Joe Biden said on Monday.

In a briefing with reporters at the same time, a senior US defence official accused Hamas of "Isis-level savagery" in an unprecedented attack.

The identities of those killed have not been announced by officials.

Mr Biden said that it is "likely" that some US citizens are among the hostages being held by Hamas.

"It's heart wrenching. These families have been torn apart by inexcusable hatred and violence," Mr Biden said in a written statement.

Mr Biden said that the US was also deploying experts to help Israel find the hostages, and was sharing intelligence.

Washington is increasing support in the form of air defence and munitions, the senior defence official said in a call with the media.

Israel says about 900 people have been killed and 100 kidnapped since Hamas militants launched the surprise attack in the early hours of Saturday.

In Gaza, more than 600 people have been killed in retaliatory Israeli air strikes.

Many still missing

Ilan Troen, a professor at Brandeis University in Massachusetts, said that his daughter Deborah Matias, 50 and her husband Shlomi, were killed when Hamas fighters attacked their community in southern Israel.

Mr Troen told CBS, the BBC's US partner, that his daughter died while shielding their son Roten.

"They made sure to fall on him and thereby saved his life," he said. "Although a bullet actually entered his abdomen, but he was saved."

On Facebook, Cincinnati native and long-time Israel resident Hannah Katsman said that her son Hayim Katsman was killed at his kibbutz near the border with Gaza.

Mr Katsman, an academic who specialised in Israel studies, was a graduate of the University of Washington.

Among the missing is 23-year-old American-Israeli Hersh Golberg-Polin, who was at a music festival in the desert which was stormed by militants.

His parents told the Jerusalem Post they received two messages from him, reading "I love you" and "I'm sorry".

"We just want him safe," Jonathan Polin, his father, said.

Another soldier with dual US-Israeli citizenship, Itay Chen, has reportedly been missing in action since Saturday.

His father, Ruby Chen, told CNN that he had sought the State Department's help in finding his son, but believes that the US is "taking a back seat" in the investigation. He added that it is "a fair assumption" to believe his son was taken to Gaza.

Another US citizen living in Israel, Abbey Onn, told MSNBC that five members of her family were taken hostage. On Saturday, she received a WhatsApp message from her family that Hamas fighters were in their home at Nir Oz near Gaza.

She later saw one of her relatives, a 12-year-old boy, in a video posted online.

More on Israel-Gaza attacks

• Follow live: Latest updates

• Music festival: Partygoers fled for lives as bullets rained down

• Gaza: Fear and chaos in Gaza as Israel strikes back

• Israel: 'Nobody could help us' - Shock and anger in Ashkelon

• Explained: What's going on in Gaza and Israel, and why now?

Global Affairs Canada has meanwhile confirmed at least one Canadian citizen is dead and two are missing.

Alexandre Look, a 33-year-old from Montreal, was killed at the music festival, his father Haim confirmed to CBC.

"He was just a normal young man trying to enjoy a slice of life in a very normal way."

Ben Mizrachi, from British Columbia, is among the missing, CTV News reported.

A former federal minister of justice, Irwin Cotler, wrote online that Vivian Silver, 75, a Canadian-Israeli, was "violently taken from her home in Kibbutz Be'eri" on Saturday and "is now being held captive by Hamas in Gaza".

The peace activist from Winnipeg is the long-time director of the Arab Jewish Center For Empowerment, Equality, and Co-operation, a non-profit that has promoted a shared society for Arabs and Jews throughout Israel.

Foreign nationals from various countries have been confirmed to have died in the attack. More than 10 British citizens are feared dead or missing, an official UK source told the BBC.