WASHINGTON, April 5 (Reuters) -

President Joe Biden took an aerial tour on Friday of the

collapsed Baltimore bridge that is blocking a key East Coast

shipping lane, and he pledged federal help in rebuilding the

span, an idea some Republican lawmakers in the U.S. Congress

have resisted.

A cargo ship crashed into the Francis Scott Key Bridge

on March 26, sending it splashing into the harbor. Work to clear

the wreckage and restore traffic through the Mid-Atlantic

state's shipping channel is ongoing.

Aboard his Marine One helicopter, Biden flew over the scene

of the disaster, where six people were killed, to get an aerial

view. He met local officials for a briefing on the economic

impact to the Baltimore port, an important shipping destination

for ships to offload automobiles.

Speaking with the fallen bridge behind him as an

imposing backdrop, Biden vowed "we will not rest" until the

bridge is rebuilt and the area is back to normal.

He called on Congress to approve funding for the new

bridge as soon as possible.

"I'm here to say your nation has your back and I mean

it," Biden said. "We're going to get this paid for."

He also vowed that the parties responsible for the

bridge collapse will help pay to repair the damage and "be held

accountable to the fullest extent the law will allow."

Biden later met the families of the six people killed in

the accident.

State and federal officials have raised alarms over the

hardships the port's closure could impose on the regional

economy with thousands of port workers already idled.

The Port of Baltimore ranks first in the U.S. for volume of

autos and light trucks and farm and construction machinery

handled, according to the state of Maryland. Most of that

traffic has been suspended since the accident, though some

terminal operations outside the affected area have resumed.

The White House's Office of Management & Budget (OMB),

in a letter to Congress on Friday, asked the federal government

to cover the bridge replacement, which federal officials say

could cost at least $2 billion.

Some Republican hardliners in the U.S. House of

Representatives oppose using new federal dollars to fund the

bridge's reconstruction. Such a request could probably pass the

Senate, controlled by Biden's fellow Democrats, but may run into

trouble in the narrowly divided House.

The House Freedom Caucus, a bloc of roughly three dozen

hardline Republicans who can wield outsized influence over House

Speaker Mike Johnson, on Friday issued a series of demands in

exchange for their cooperation.

The six victims of the bridge collapse were all immigrants

from Mexico and Central America, who were fixing potholes on the

road surface of the bridge when it collapsed. Four of the bodies

have still not been recovered, but all are presumed dead.

Biden's meeting with the families of these immigrant workers

comes as his rival Republican presidential nominee Donald Trump

has ramped up anti-immigrant rhetoric and cast migrants as

dangerous criminals "poisoning the blood" of America.

FUNDING FOR THE BRIDGE

Hours after the bridge collapse, Biden said the U.S.

government would "pay the entire cost" of reconstruction and his

administration announced $60 million in emergency relief last

week.

The administration will pursue all avenues to recover costs

and "ensure that any compensation for damages or insurance

proceeds collected will reduce costs for the American people,"

Office of Management and Budget Director Shalanda Young wrote on

Friday.

White House officials have held talks in recent weeks with

Johnson's office over billions in aid for Ukraine and Israel as

well as money for the collapsed bridge, according to two

officials familiar with conversations who asked not to be named.

The spending measures separately have bipartisan support,

but the White House is aware that Johnson must satisfy his

hardline colleagues, which means many spending proposals will be

tethered together in order to pass, the officials said.

The Freedom Caucus, whose members helped oust Johnson's

predecessor last year, said Congress should seek "maximum

liability" from foreign shipping companies.

It also demanded that any aid be fully offset with

spending cuts and that the Endangered Species Act and other

regulations are waived to avoid delays.