*

Harris and Trump ramp up outreach in battleground states

*

Harris says U.S. Steel should remain domestically owned

*

Biden and Harris met with US hostage deal negotiating team

*

Biden administration faces criticism over ceasefire

strategy

(Adds details on labor vote)

By Jeff Mason, Steve Holland and Kanishka Singh

PITTSBURGH, Sept 2 (Reuters) - Democratic presidential

candidate Kamala Harris said on Monday that U.S. Steel

should remain in domestic hands, making a pitch alongside

President Joe Biden to working-class voters in Pennsylvania who

are also being courted by her rival.

The event on Labor Day, a U.S. holiday that signifies the

start of the post-summer sprint to the Nov. 5 election, marked

Harris and Biden's first appearance together at a campaign rally

since she officially became the Democratic nominee.

Harris used campaign events on Monday in Michigan and

Pennsylvania, two battleground states, to court the crucial

labor vote. At a packed union hall in Pittsburgh, she echoed

Biden's concern over U.S. Steel Corp being acquired by

Japan's Nippon Steel ( NISTF ).

"U.S. Steel is a historic American company, and it is vital

for our nation to maintain strong American steel companies,"

Harris said at the rally. "U.S. Steel should remain

American-owned and American-operated."

Biden said Harris would build on the progress they had made

during his administration to improve the lives of union workers

and that he would do everything he could to help.

"I'll be on the sidelines," he said.

The Harris campaign has sought to appeal to union workers in

much the same way as Biden has throughout his presidency. The

Democrats aim to keep union workers from being tempted to vote

for former Republican President Donald Trump, who also has

blue-collar appeal.

At the rally in Pittsburgh, Todd Hamer, 48, said he thought

Biden's support for labor would help Harris.

"She's new," Hamer said. "We're all still learning (about

her), but she does have a deep history and I think she's going

to continue to stand by labor leaders and unions to help support

unions and their cause."

Trump, who is locked in a tight race with Harris, stayed off

the campaign trail on Monday. His campaign has announced several

events for later in the week, including in North Carolina and

Wisconsin.

The Harris campaign mocked Trump's lack of public

appearances on Monday. "Trump ... golfing?" the Harris campaign

said on X.

A Trump campaign aide said Harris' decision to rally voters

with Biden gave the Trump team another opportunity to tie the

Democrats together politically.

Trump has said he would move to block the U.S. Steel deal, a

potential merger that has stirred anxiety among some unionized

workers, a key voting bloc in Pennsylvania and the other "Rust

Belt" swing states likely to determine the results of the

election.

Responding to Harris' criticism, U.S. Steel said it was

committed to the deal with Nippon Steel ( NISTF ).

GAZA WAR CASTS SHADOW

Both Harris and Trump are expected to ramp up outreach to

voters in the coming weeks, especially in swing states that

could prove decisive in the election.

Harris is hoping to keep up the enthusiasm her entry into

the race has sparked among Democrats, who are donating record

amounts of money and volunteering by the tens of thousands.

A recent Reuters/Ipsos poll found Harris was leading Trump

nationally 45% to 41%.

On Monday, developments in the Middle East over talks on a

deal to reach a Gaza ceasefire and release hostages cast a

shadow on campaigning.

Over the weekend, Israel recovered the bodies of six

hostages from a tunnel in Gaza where it said they were recently

killed by Palestinian Islamist group Hamas, sparking sharp

criticism of the Biden administration's Gaza ceasefire strategy.

Biden told reporters earlier on Monday he did not think

Israeli Prime Minister Benjamin Netanyahu was doing enough to

secure a hostage deal.

Late on Monday, Biden said he would "eventually" talk to

Netanyahu but declined to specify when.

Some 1,200 Israelis were killed in Hamas' surprise attack on

Oct. 7 and around 250 were taken hostage, according to Israeli

tallies.

Health authorities in Gaza say more than 40,000 Palestinians

have been killed in the Israeli assault on the enclave since

that has also displaced nearly its entire 2.3 million

population, caused a hunger crisis and led to genocide

allegations at the World Court that Israel denies.

Biden and Harris also met with the U.S. hostage negotiation

team in Washington on Monday and discussed the next steps in

efforts to free the remaining captives.

The war is weighing on the U.S. election, with

pro-Palestinian activists threatening to ramp up protests

against Harris on the campaign trail. Thousands of

pro-Palestinian activists opposing U.S. support for Israel's war

in Gaza held a protest in New York City on Monday.