Armstrong left his apartment in Ashkelon, a city roughly eight miles from the Gaza border.
"The rocket landed right in front, it could have easily hit my apartment," Armstrong told 6abc in an interview on Monday morning.
SEE ALSO: 9 Americans dead following attacks in Israel, officials say
9 Americans dead following attacks in Israel, officials say
"I have a few teammates that live north of Tel Aviv. We had called them and said, 'Hey, listen, there's a bunch of bombs going on, missiles, close to my apartment'. One had landed about 100 feet from where I stayed, so I was like, 'Man, I can't stay here'," Armstrong said.
He is now staying with those teammates.
Armstrong is the founder and CEO of JAB Camps. Action News spoke to him last summer in Philadelphia about his goal to use the sport as a way to combat antisemitism, racism and hate.
SEE ALSO: Pro basketball player from Israel brings his passion home to Philadelphia
Pro basketball player from Israel brings his passion home to Philadelphia
Many international airlines have now suspended flights from Tel Aviv.
"At first there were a lot of teams here in Israel sending the foreign players when the war started happening, to Greece and Cyprus, locations that were close, but since yesterday there are no flights from United, American Airlines, any flights outside Israeli airlines," Armstrong said.
Armstrong's mind is with the many victims of the attacks and his hope is for a swift resolution.
SEE ALSO: Israel intensifies Gaza strikes, more than 1,100 dead in the fighting
"I'm a son of a 9/11 survivor, so my sympathies are out to families. My prayers are to everyone that's impacted, the IDF, kids that were kidnapped by the Hamas," said Armstrong.
"My goal is to keep myself and my teammates as safe as we can be, out of harm's way, and pray to God things get resolved quickly and that we can end this war."
State Department spokesperson Matt Miller confirmed nine Americans were killed in Israel over the weekend.