WASHINGTON, May 9 (Reuters) - Billions of dollars worth

of U.S. weaponry remains in the pipeline for Israel, despite the

delay of one shipment of bombs and a review of others by

President Joe Biden's administration, concerned their use in an

assault could wreak more devastation on Palestinian civilians.

A senior U.S. official said this week that the

administration had reviewed the delivery of weapons that Israel

might use for a major invasion of Rafah, a southern Gaza city

where over 1 million civilians have sought refuge, and as a

result paused a shipment of bombs to Israel.

Washington has long urged Prime Minister Benjamin

Netanyahu's government not to invade Rafah without safeguards

for civilians, seven months into a war that has devastated Gaza.

Congressional aides estimated the delayed bomb shipment's

value as "tens of millions" of U.S. dollars.

A wide range of other military equipment is due to go to

Israel, including joint direct attack munitions (JDAMS), which

convert dumb bombs into precision weapons; and tank rounds,

mortars and armored tactical vehicles, Senator Jim Risch, the

top Republican on the Senate Foreign Relations Committee, told

reporters.

Risch said those munitions were not moving through the

approval process as quickly as they should be, noting some had

been in the works since December, while assistance for Israel

more typically sails through the review process within weeks.

Biden administration officials have said they are reviewing

additional arms sales, and Biden warned Israel in a CNN

interview on Wednesday that the U.S. would stop supplying

weapons if Israeli forces make a major invasion of Rafah.

Israel's assault on Gaza was triggered by an Oct. 7 attack

by Islamist Hamas militants, which by its tallies killed 1,200.

The subsequent Israeli bombardment has killed some 35,000

Palestinians, according to local health authorities, and

displaced the majority of Gaza's 2.3 million people.

Separately, Representative Gregory Meeks, top Democrat on

the House of Representatives Foreign Affairs Committee, has put

a hold on an $18 billion arms transfer of package for Israel

that would include dozens of Boeing Co. ( BA ) F-15 aircraft while he

awaits more information about how Israel would use them.

Biden's support for Israel in its war against Hamas has

emerged as a political liability for the president, particularly

among young Democrats, as he runs for re-election this year. It

fueled a wave of "uncommitted" protest votes in primaries and

has driven pro-Palestinian protests at U.S. universities.

None of those weapons agreements are part of a spending

package Biden signed last month that included about $26 billion

to support Israel and provide humanitarian aid.

Risch and Meeks are two of the four U.S. lawmakers - the

chair and ranking member of Senate Foreign Relations and chair

and ranking member on House Foreign Affairs - who review major

foreign weapons deals.

'FINGERNAILS'

Netanyahu issued a video statement on Thursday saying

Israelis "would fight with their fingernails" in an apparent

rebuff of Biden.

Republicans accused Biden of backing down on his commitments

to Israel. "If the Commander-in-Chief can't muster the political

courage to stand up to radicals on his left flank and stand up

for an ally at war, the consequences will be grave," Senate

Republican leader Mitch McConnell said in a Senate speech.

Ten other Senate Republicans held a press conference to

announce a non-binding resolution condemning "any action by the

Biden Administration to withhold or restrict weapons for

Israel."

White House National Security spokesperson John Kirby told

reporters Israel was still getting the weapons it needs to

defend itself. "He's (Biden's) going to continue to provide

Israel with the capabilities that it needs, all of them," Kirby

said.

Some Congressional Democrats welcomed Biden's action.

Senator Chris Murphy, the Democratic chair of the Foreign

Relations Mideast subcommittee, cited concern about Rafah.

"I do not think it is our strategic or moral interest to

help Israel conduct a campaign in Rafah that is likely to kill

thousands of innocent civilians and not likely impact Hamas'

long-term strength in a meaningful way," he told Reuters.