(Recasts, updates prices)

* Samsung forecasts jump in April-June operating profit

* Seoul shares tumble 8%, triggering circuit breakers

* MSCI Asia-Pacific ex-Japan loses 2.6%, Nikkei falls 2.4%

* Oil prices edge slightly higher after hitting pre-Iran war

levels Monday

By Satoshi Sugiyama

TOKYO, July 7 (Reuters) - Asian stocks declined on Tuesday,

with South Korea leading losses after Samsung Electronics' ( SSNLF )

forecast triggered a reassessment of stretched valuations tied

to the AI trade, while oil prices largely stabilised as

investors refocused on supply and demand.

Samsung Electronics ( SSNLF ), the world's largest memory

chipmaker, estimated April-June operating profit at 89.4

trillion won ($58.44 billion), an eye-popping 19-fold jump and a

third straight quarter of record operating profit.

Still, South Korean shares slumped 8%, triggering

circuit breakers as Samsung Electronics ( SSNLF ) lost 9.8%, reflecting

concerns over the durability of the AI-driven chip boom.

The AI jitter rippled across Asian markets, with MSCI's

broadest index of Asia-Pacific shares outside Japan

falling 2.6% and chipmaker-heavy Taiwan

down 1.8%. Japan's Nikkei shed 2.4%.

The recent sharp rally in AI-related shares has likely been

driven by concerns over the economy and inflation, with worries

about the outlook - including worsening tensions involving Iran

- prompting investors to seek refuge in the sector, said Toru

Suehiro, chief economist at Daiwa Securities.

"While it would be healthier for share prices to move in

line with business conditions and the real economy, those

conditions do not change that rapidly," Suehiro said in a note,

adding that markets were therefore likely to remain range-bound.

Morgan Stanley said in a note dated Monday that the recent

weakness in U.S. semiconductor stocks is a sign that market

gains are broadening, with investors likely to turn toward AI

"hyperscalers" as well as consumer discretionary, transport and

biotechnology shares.

In early European trades, the pan-region Euro Stoxx 50

futures lost 0.4%, German DAX futures fell 0.3%

and FTSE futures were up almost 0.1%.

U.S. S&P 500 E-minis dipped 0.3%, Nasdaq 100

E-minis retreated 1.2% and Dow E-minis were

down 0.02%.

OIL MARKET STEADY

Oil edged higher, but gains were limited after prices hit

pre-Iran war levels on Monday. U.S. crude rose 0.85% to

$69.13 a barrel and Brent rose to $72.62 per barrel, up

0.88% on the day.

U.S. President Donald Trump, who has pressured Europe to

increase defence spending and clashed with European leaders over

the Iran war and Greenland, will attend a NATO meeting in Turkey

beginning on Tuesday.

Trump said on Monday the U.S. would either reach a deal with

Iran or "finish the job," renewing his threat of military action

as Tehran projects defiance following the funeral of former

Supreme Leader Ayatollah Ali Khamenei.

In currency markets, the dollar index, which measures

the greenback against a basket of currencies including the yen

and the euro, traded at 100.88, with the euro down 0.03%

at $1.1436.

The yen bounced back from the weaker side of 162 per

dollar, near 40-year lows, and was last up 0.17% at 161.79 per

dollar. Traders remained on watch for intervention amid signs of

a possible shift in strategy by Japanese authorities.

On Tuesday, Japanese government bond yields fell from

multi-decade highs after a sale of super-long-term debt showed

strong demand. The yield on benchmark U.S. 10-year notes

rose 1.62 basis points to 4.495%, from 4.479% late

on Monday.

Fed watchers will get another glimpse into how new Chair

Kevin Warsh steers the central bank when it releases Federal

Open Market Committee minutes on Wednesday, the first of his

tenure.

In commodity markets, gold lost 0.91% at $4,125.59 an

ounce, trading below a two-week high. Silver fell

2.17% to $60.73 an ounce and copper declined 0.58% to

$13,326.00 a ton.

(Reporting by Satoshi Sugiyama; Editing by Jacqueline Wong and

Lincoln Feast.)