"You let the disease spread and the result is the horrific attacks on Jews we saw today," Israel's Prime Minister Benjamin Netanyahu said.

"We were standing and suddenly came the 'boom boom,' and everybody fell down," his wife said.

Rabbi Eli Schlanger, who had recently welcomed a new son just two months ago has been named as one of the first victims in Sunday's deadly terrorist attack in Sydney which targeted worshippers at a Hanukkah event.

"I saw blood gushing in front of me. I saw people hit, saw people fall to the ground," the human rights lawyer said.

A person of interest has been arrested in the shooting at Brown University that left two people dead and nine wounded, authorities in Rhode Island announced on Sunday morning.