US Secretary of State Marco Rubio said he expedited the delivery of $4 billion in military assistance to Israel.

"I have signed a declaration to use emergency authorities to expedite the delivery of approximately $4 billion in military assistance to Israel," Rubio said in a statement on Saturday.

"The decision to reverse the Biden Administration's partial arms embargo, which wrongly withheld a number of weapons and ammunition from Israel, is yet another sign that Israel has no greater ally in the White House than President Trump," he added.

His statement came one day after the State Department said it approved potential foreign military sales to Israel worth $3 billion, which included munitions, guidance kits and Caterpillar D9 bulldozers.

In a statement Friday, the agency stated that Rubio determined "emergency exists", requiring the immediate sales to Israel, waiving congressional review requirements.

Rubio said since Trump took office in late January, his administration has approved nearly $12 billion in major foreign military sales to Israel.

"This important decision coincides with President Trump's repeal of a Biden-era memorandum which had imposed baseless and politicised conditions on military assistance to Israel at a time when our close ally was fighting a war of survival on multiple fronts against Iran and terror proxies," Rubio said in Saturday's statement.

"The Trump Administration will continue to use all available tools to fulfill America's long-standing commitment to Israel's security, including means to counter security threats," he added.

The US has faced longstanding criticism for supporting Israel's military assault on Gaza amid widespread reports of violations of international and US laws.