WASHINGTON (Reuters) -The U.S. Senate late on Tuesday advanced President Donald Trump's request to slash billions in spending on foreign aid and public broadcasting previously approved by Congress, the latest test of Trump's control over his fellow Republicans.

However, PEPFAR, a global program to fight HIV/AIDS launched in 2003 by then-Republican President George W. Bush, is being exempted after objections from lawmakers in both parties, bringing the size of the package of cuts to $9 billion from $9.4 billion.

Russell Vought, director of the Office of Management and Budget, told reporters after lunch with Republican senators that Trump could accept a change in the measure to exempt PEPFAR.

"There is a substitute amendment that does not include the PEPFAR rescission and we're fine with that," Vought said.

In initial votes on Tuesday, Republicans narrowly fended off solid Democratic opposition and cleared the bill over two procedural hurdles. Vice President JD Vance was needed to break a 50-50 tie in each of those tallies.

Further votes were expected this week.

Congress has until Friday to pass the rescissions package, originally a request to claw back $8.3 billion in foreign aid funding and $1.1 billion for public broadcasting. Otherwise, the request would expire and the White House will be required to adhere to spending plans passed by Congress.

Three of the Senate's 53 Republicans voted against moving the legislation closer to passage - Senators Lisa Murkowski of Alaska, Mitch McConnell of Kentucky and Susan Collins of Maine.

"You don't need to gut the entire Corporation for Public Broadcasting," Senator Lisa Murkowski, an Alaska moderate, said in a Senate speech.

She said the Trump administration also had not provided assurances that battles against diseases such as malaria and polio worldwide would be maintained, along with programs including family planning and pandemic prevention. But most of all, Murkowski said, Congress must assert its role in deciding how federal funds were spent.

If the Senate passes the bill without the PEPFAR cuts, the measure must go back to the House of Representatives for a vote before it can be sent to the White House for Trump to sign into law. Senate Majority Leader John Thune of South Dakota, a Republican, said he expected the House would act quickly to pass the measure.

The amounts at stake are extremely small in the context of the sprawling federal budget, which totaled $6.8 trillion in the fiscal year ended September 30. Yet the proposed cuts have raised the hackles of Democrats and a handful of Republicans who saw an attempt to erode Congress's constitutionally mandated authority over spending.

They also represent only a tiny portion of all of the funds approved by Congress that the Trump administration has held up as it has pursued sweeping cuts to the federal government, including slashing thousands of jobs.

As of mid-June, Trump was blocking $425 billion in such funds, according to Democratic lawmakers tracking frozen funding.

LIFESAVING PROGRAMS

The foreign aid initiatives in Trump's request for cuts included lifesaving support for women and children's health and the fight against HIV/AIDS that have long had strong bipartisan support. PEPFAR is credited with saving 26 million lives.

The package also cuts funds supporting public broadcasting, which can be the main source of news and emergency information in rural parts of the U.S. Senator Mike Rounds, a South Dakota Republican, was concerned about funding cuts to Native American radio stations, but said on Tuesday he would support the rescissions package after the administration promised to fund some tribal broadcasters separately.

Democrats also have said the U.S. withdrawal of "soft power" efforts from the international stage, such as limited emergency assistance after an earthquake in Myanmar, strengthens global adversaries like Russia and China.

"It still leaves an enormous vacuum that China and Russia will fill," Senator Charles Schumer of New York, the chamber's Democratic leader, said.

Senator Susan Collins of Maine, who chairs the Appropriations Committee, had said she opposed Trump's request to cut the PEPFAR funding. After the lunch meeting with Vought, she said she still wanted detailed information about the proposals.

FUNDING POWER

Standalone presidential rescissions packages have not passed in years, with lawmakers reluctant to cede their constitutionally mandated control of government spending. During Trump's first term in 2018, Congress members rejected Trump's request to revoke $15 billion in spending.

Trump's Republicans hold narrow majorities in the Senate and House. So far, they have shown little appetite for opposing his policies.

The rescissions legislation passed the House by 214-212 last month. Four Republicans joined 208 Democrats in voting against it.

These cuts would overturn bipartisan spending agreements most recently passed in a full-year stopgap funding bill in March. Democrats warn a partisan cut now could make it more difficult to negotiate government funding bills that must pass by September 30 to avoid a shutdown.

Appropriations bills require 60 votes to move ahead in the Senate, but the rescissions package needs just 51, meaning Republicans can pass it without Democratic support.

"We're going to have to work our way through that issue," Rounds said on Tuesday, adding he felt confident Trump's budget office would follow funding guidelines to redirect dollars to tribal media stations.