*

Trump says U.S. "may" or "may not" join Israeli bombing of

Iran

*

Oil hovers near 4-1/2-month peak on risks of supply shock

*

Dollar firm on haven demand despite mixed signals from Fed

By Kevin Buckland

TOKYO, June 19 (Reuters) - Stock markets in Asia edged

lower on Thursday while safe havens such as gold and the

Japanese yen gained as investors remained on edge over the

possible entry of the United States into the week-old

Israel-Iran air war.

President Donald Trump kept the world guessing about whether

the United States will join Israel's bombardment of Iranian

nuclear sites, telling reporters outside the White House on

Thursday, "I may do it. I may not do it."

The Wall Street Journal said Trump had told senior aides he

approved attack plans on Iran but was holding off on giving the

final order to see if Tehran would abandon its nuclear

programme.

Japan's Nikkei sank 0.8%, with additional downward

pressure stemming from a stronger yen, which reduces the value

of overseas revenues for the country's heavyweight exporters.

Taiwan's stock benchmark slid 0.9%, and Hong Kong's

Hang Seng declined 0.8%.

U.S. S&P 500 futures pointed 0.4% lower, although

most U.S. markets - including Wall Street and the Treasury

market - are closed on Thursday for a national holiday.

Gold advanced 0.3% to $3,378 per ounce.

"Market participants remain edgy and uncertain," said Kyle

Rodda, senior financial markets analyst at Capital.com.

"Speculation remains rife - fed probably strategically by

the Trump administration - that the U.S. will intervene,

something that would mark a material escalation and could invite

direct retaliation against the U.S. by Iran," he said. "Such a

scenario would raise the risk of a greater regional conflict,

with implications for global energy supply and probably economic

growth."

Brent crude edged down to $76.32 per barrel, but

remained not far from the 4-1/2-month peak of $78.50 reached on

Friday.

The yen gained 0.2% to 144.92 per dollar, while

the U.S. currency itself was also in demand as a haven, gaining

0.1% to $1.1472 per euro and 0.2% to $1.3398 versus

sterling.

The Swiss franc edged down 0.1% to 0.8193 per dollar.

The Bank of England and Swiss National Bank both announce

policy decisions later in the day, with the BOE widely expected

to keep interest rates steady while the SNB is seen as likely to

cut rates by 25 basis points.

Overnight, the Federal Reserve delivered some mixed signals

to markets. Policymakers held rates steady, as expected, and

retained projections for two quarter-point rate cuts this year.

However, Fed Chair Jerome Powell struck a cautious note

about further easing ahead, saying at his press conference later

that he expects "meaningful" inflation ahead as a result of

Trump's aggressive trade tariffs.