Sen. Cory Booker was in Jerusalem when the attacks in Israel began.
He sought refuge in a hotel bomb shelter with frightened families and fellow Americans.
Sen. Booker, a member of the Senate Foreign Relations Committee, arrived for the Abraham Accords summit.
He expressed sorrow for the casualties and injuries caused by the "staggering" attacks.
Secretary of State Antony Blinken's team is working to confirm reports of American casualties.
Sen. Booker reaffirmed his commitment to support Israel's security and regional stability.
The Senate will reconvene on Monday, Oct. 16, following the recess.