The Trump administration, which took office on January 20, has approved nearly $US12 billion ($A19 billion) in major foreign military sales to Israel, Rubio said in a statement on Saturday.
The US "will continue to use all available tools to fulfill America's long-standing commitment to Israel's security, including means to counter security threats".
Rubio said he had used emergency authority to expedite the delivery of military assistance to Israel to its Middle East ally, now in a fragile ceasefire with Hamas militants in their war in Gaza.
The Pentagon said on Friday that the State Department had approved the potential sale of nearly $US3 billion ($A4.8 billion) worth of bombs, demolition kits and other weaponry to Israel.
The administration notified Congress of those prospective weapons sales on an emergency basis, sidestepping a long-standing practice of giving the chairs and ranking members of the House Foreign Affairs and Senate Foreign Relations Committees the opportunity to review the sale and ask for more information before making a formal notification to Congress.
Friday's announcements marked the second time in recent weeks that President Donald Trump's administration has declared an emergency to quickly approve weapons sales to Israel.
The Biden administration also used emergency authority to approve the sale of arms to Israel without congressional review.
On Monday, the Trump administration rescinded a Biden-era order requiring it to report potential violations of international law involving US-supplied weapons by allies, including Israel. It has also eliminated most US humanitarian foreign aid.
The January 19 Israel-Hamas ceasefire agreement halted 15 months of fighting and paved the way for talks on ending the war, while leading to the release of 44 Israeli hostages held in Gaza and around 2000 Palestinian prisoners and detainees held by Israel.
Hours after the first phase of the agreed ceasefire was set to expire, Israel said early on Sunday it would adopt a proposal by Trump's envoy, Steve Witkoff, for a temporary ceasefire in Gaza for the Ramadan and Passover periods.
Israel and Hamas have accused each other of violating the ceasefire, casting doubt over the second phase of the deal meant to include releases of additional hostages and prisoners as well as steps toward a permanent end of the war.Â
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