Israel is calling up thousands of reservists, including Americans, and has massed troops along the border with Gaza, signaling a ground invasion of the densely populated seaside strip could be imminent.
The attack by Palestinian militants on Jerusalem Friday, along with an earlier strike on the metropolis of Tel Aviv, was a major escalation of hostilities as Israel pressed forward with a relentless campaign of airstrikes in the Gaza Strip.
The news stirred the tri-state Friday, sparking a small protest in front of the Israeli consulate on Second Avenue and putting some Americans on notice that they might be soon heading to the Middle East.
Harvard medical student Edan Razinovsky, 26, who was born in Israel and moved to White Plains in Westchester when he was about 3 years old, was studying for his physics midterm when he learned his unit had been activated.
"I have now a choice, because I'm a U.S. citizen and live in the States, and I'm in school," Razinovsky told NBC 4 New York over Skype. "I have a choice to go back. And I'm torn between that choice."
Razinovsky called the situation "surreal."
"Nobody ever expects that kind of phone call," he said. "That voicemail -- 'Hey, it's war time, and it's time for you to go.'"
He is now weighing his decision as he thinks of his unit members in the army.
"It's hard to say where you're going to be next Tuesday: am I going to be in a war zone or am I going to be taking my physics midterm?" he said.
Abdellah Karram, from northern New Jersey, said he's planning to travel to Gaza to see his family near the line of fire.
"It is a little nervewracking, but I'm not just going to leave my people behind," he said. "I'm going to go visit my family."
Others are praying for peace -- an outcome that seems all too elusive.
"I do respect the people being targeted on both sides," said Alexis Abuhadba, of Wyckoff, N.J. "It's inhumane in any way. If you're hurting a life and it's an Israeli or a Palestinian, it's wrong."