TOKYO, May 11 (Reuters) - Japanese government bonds

(JGBs) slumped on Monday as inflationary concerns mounted ahead

of a debt sale, with the U.S.-Iran stalemate fuelling

energy-driven price pressures.

The benchmark 10-year JGB yield rose 4 basis

points (bps) to 2.515%, closing in on the 29-year high of 2.535%

reached on April 30, held at 2.475%. The 20-year JGB yield

climbed 4.5 bps to 3.4%.

Yields move inversely to bond prices.

Oil prices jumped on Monday after the United States and Iran

failed to agree to a peace proposal drafted by Washington while

the Strait of Hormuz, which typically handled about a fifth of

global oil and liquefied natural gas flows prior to the Middle

East war, remained largely closed.

Japan's Ministry of Finance plans to auction about 2.6

trillion yen ($16.57 billion) in 10-year JGBs on Tuesday.

Investors are likely to be cautious ahead of the sale and

policy announcements that may emerge from a visit to Tokyo by

U.S. Treasury Secretary Scott Bessent, according to Takayuki

Miyajima, chief economist, Sony Financial Group.

"Concerns about oil price-driven inflation appear to be

exerting upward pressure on domestic interest rates," Miyajima

said in a note.

"The market is likely to remain weighed down, as

participants keep a close eye on developments in the Middle East

and price trends."

The 30-year yield added 4.5 bps to 3.76%,

while the yield on the 40-year JGB, Japan's

longest tenor, rose 5 bps to 4.025%.

The two-year yield, the one most sensitive to

Bank of Japan policy rates, increased 1.5 bps to 1.385%. The

five-year yield rose 3 bps to 1.890%.

The BOJ said on Monday it has appointed Kazuhiro Masaki, a

veteran career central banker with expertise on monetary policy,

as executive director overseeing its international affairs.

($1 = 156.9100 yen)