(Updates for European morning trading)

* Authorities said to have intervened last week to

support currency

* Japan closed for Golden Week holiday

* Trump says US to aid ships stranded behind the Strait

of Hormuz

By Samuel Indyk and Gregor Stuart Hunter

LONDON, May 4 (Reuters) - The yen saw another sharp,

intraday jump against the dollar on Monday, prompting

speculation about another bout of intervention by Japanese

authorities to bolster the battered currency.

The yen climbed as much as 0.75% to 155.69 before

unwinding, with much of the appreciation coming during a

nine-minute stretch around midday Singapore time (0400 GMT).

The Japanese currency was last up 0.1% at 156.84, after

rising about 1.5% last week, its largest weekly jump since

February. It was also slightly stronger against the euro

and pound.

"We suspect it to be intervention. My view would be that

officials are intending to put a line in the sand at 160 (per

dollar)," said Amanda Sundström, FX strategist at SEB.

Ministry of Finance officials did not immediately respond to

requests for comment after the move on Monday.

Tokyo officials declined to confirm whether they had

intervened last week, but sources told Reuters the authorities

did undertake yen-buying activity for the first time in two

years.

Money market data on Friday showed Tokyo may have spent as much

as 5.48 trillion yen ($35 billion) buying the yen last week.

"The primary focus will be whether further intervention

occurs, noting that Japan is closed for the Golden Week holiday

and there will be thinner liquidity during this time," said

Mahjabeen Zaman, head of FX research at ANZ Bank in Sydney.

"And more importantly, whether the U.S. will join Japan's

efforts in supporting the yen," she added. "If the yen weakens

further, you could argue that the likelihood of bilateral

intervention increases."

IRAN WAR STILL IN FOCUS

Markets remained cautious at the start of the trading week after

U.S. President Donald Trump said they would start an effort on

Monday morning to free ships stranded in the Strait of Hormuz as

a "humanitarian gesture" to aid neutral countries in the

U.S.-Israeli war with Iran.

Iran warned the U.S. Navy not to enter the Strait of Hormuz,

saying it would "respond harshly" to any threat.

The U.S. dollar index, which measures the greenback's

strength against a basket of six currencies, was up 0.1% at

98.264.

The euro was little changed at $1.1717 after German

Chancellor Friedrich Merz sought to downplay a rift with Trump

after the U.S. announced plans to draw down troops from

Germany.

The country's economy ministry said on Sunday that Berlin is

also in touch with the European Commission as it holds talks

with Washington, after Trump said on Friday he would increase

tariffs on cars and trucks from the EU to 25%.

"In the grand scheme of things, it (auto tariffs) is

definitely not a positive, but it's not going to be the main

driver," SEB's Sundström said.

"The situation in the Middle East is definitely the dominant

factor now."

The British pound was down 0.1% at $1.3564. British

markets are closed on Monday for a public holiday.

The Australian dollar was down 0.2% at $0.7192, while

its kiwi counterpart advanced 0.1% at $0.59.

The Reserve Bank of Australia is due to announce its next policy

decision on Tuesday, with the majority of analysts polled by

Reuters expecting a hike in the cash rate to 4.35%. Last week,

Australia's top two grocers warned of growing price pressures as

the Iran war drives up fuel and raw material costs for

suppliers.

Bitcoin was up 1.1% at $79,744, after earlier trading

above $80,000 for the first time since January 31.