By Ernest Scheyder

April 29 (Reuters) - Central bank gold buying and global trade tensions are likely to push bullion prices to near $5,000 an ounce by 2028, billionaire investor John Paulson said in an interview during which he reinforced his commitment to U.S. mining projects

The price forecast is one of the most bullish yet as banks and others move to increase their own estimates after gold hit a record high just above $3,500 last week. Deutsche Bank DBKGn.DE, for one, expects bullion to hit $3,700 an ounce by next year.

Already the largest shareholder in Idaho gold and antimony developer Perpetua Resources PPTA.O, Paulson last week bought a 40% stake in NovaGold's NG.TO Donlin gold project in Alaska from Barrick ABX.TO.

Asked where he expects bullion prices to head, Paulson cited a recent estimate put to him for levels at the "high $4,000 range" within three years.

"It's a well-informed prediction. I think that's a reasonable number," Paulson said.

"As central banks and people look to put their money in a more stable source... I think gold will increase its position in the world," he added.

The New York-based investor cited Western confiscation of Russia's foreign reserve holdings after Moscow's invasion of Ukraine as a catalyst for the world's central banks - especially China's - to pile into gold.

"When the war started, (Russia) kept their physical gold, that was safe, but all their cash - the paper reserves - were confiscated," Paulson said.

"So that caused other central banks to wake up and say ... 'What happens if there's a conflict with the U.S.? Could the U.S. keep our treasuries, and all our savings would disappear?'" Paulson said.

He added that he sees global trade uncertainty, fueled in part by Washington's tariffs, as further underpinning gold.

"The best place to go if your faith in the (U.S.) dollar diminishes is gold as a reserve currency," said Paulson, who was considered for a role in U.S. President Donald Trump's second-term cabinet.

Paulson declined to discuss details of conversations with Trump, but said the president has been "very pro on America first and the golden age of America, and bringing manufacturing and mining back to America."

MINES

Paulson, who has long invested in gold, said he has no interest in expanding into copper or other metals. "Other minerals are a whole different world, so we're concentrating our efforts in gold," he said.

In Idaho, Paulson is the largest shareholder in Perpetua, which received its federal mining permit in January, is applying for funding from the U.S. Export-Import Bank, and has received support from Trump's White House.

Perpetua's gold production is seen as financially buttressing the mine's antimony production and ensuring a domestic supply of the metal - used in bullets and other weaponry - for the Pentagon. China has blocked antimony exports to the U.S.

Perpetua is working with Sunshine Silver & Refining - backed by metals investor Thomas Kaplan's Electrum Group - to build an antimony refinery. Sunshine holds permits to build such a refinery, which would supply 40% of the nation's needs.

"It's a very well-established (refining) process," said Kaplan. "We're just upgrading it and putting it back into production."In Alaska, the Donlin project has federal permits and Paulson said should have operating costs around $1,000 an ounce, far below current gold prices.

Paulson and Electrum are also invested in International Tower Hill ITH.TO, which is developing an Alaska gold mine, as well as Trilogy Metals TMQ.TO, which aims to develop projects in Alaska's Ambler district.

(Reporting by Ernest Scheyder; Editing by Veronica Brown and Jan Harvey)

((ernest.scheyder@thomsonreuters.com; X: @ErnestScheyder; +1-469-691-7667; Reuters Messaging: ernest.scheyder.thomsonreuters.com@reuters.net))