* Futures up: Dow 2.23%, S&P 500 2.44%, Nasdaq 3.16%

* Oil stocks tumble as crude prices slump over 16%

* Airlines, cruise operators rally on lower oil prices

(Updates with stocks, details and comments)

By Johann M Cherian and Purvi Agarwal

April 8 (Reuters) - U.S. stock index futures climbed on

Wednesday as investors breathed a sigh of relief after the U.S.

and Iran agreed to a two-week ceasefire, sending crude prices

lower on expectations that energy supplies through the Strait of

Hormuz could resume.

The announcementcame less than two hours before U.S.

President Donald Trump's deadline, in a sharp turnaround from

his previous warning of wiping out "a whole civilization" if

Tehran did not reopen the Strait of Hormuz, the narrow waterway

that typically handles about one-fifth of global oil trade.

Global assets staged a sharp rally: Equity indexes in Asian

and European markets climbed between 4% and 5%, while crude

prices slid 16% to nearly $90 a barrel. The dollar, which had

attracted safe-haven interest over the past month, weakened 1%

against the Japanese yen.

"The rally will need to be backed up by tangible progress in

negotiations to hold. The underlying question of whether Iran

will permanently reopen the Strait of Hormuz and whether a

lasting deal can be reached is still very much unresolved," said

Josh Gilbert, market analyst for eToro.

"If the two weeks pass without a deal, expect a sharp and

unforgiving reversal of this relief rally."

The ceasefire brought immediate relief to investors after

weeks of conflicting signals from Trump and Iran that had

dragged the conflict into a second month.

At 04:05 a.m. ET, Dow E-minis were up 1,045 points,

or 2.23%, S&P 500 E-minis were up 162.25 points, or

2.44%, and Nasdaq 100 E-minis were up 771.25 points, or

3.16%.

Futures tracking the rate-sensitive Russell 2000 Index

jumped 3.6% while the CBOE Volatility Index

slumped 5.01 points to 20.77, its lowest point in more than two

weeks.

U.S. energy stocks tracked global oil prices and tumbled in

premarket trading. Shares of Exxon Mobil ( XOM ) shed 6.2%,

Chevron ( CVX ) dropped 5.4%, and Occidental Petroleum ( OXY )

lost 7.8%.

Stocks linked to travel and leisure sectors edged higher.

Shares of American Airlines and Delta Airlines

jumped 7.3% and 6.8%, respectively, while cruise operators

Carnival and Norwegian Cruise Line added 9.4%

and 8.1%, respectively.

Big banks also nudged higher prior to the bell, with

JPMorgan Chase ( JPM ), Bank of America ( BAC ) and Wells Fargo ( WFC )

up more than 2% each.

Beyond the immediate relief, global investors remain keen to

see whether the ceasefire leads to a broader resolution before

placing major bets.

Still, concerns persisted that a prolonged conflict and

soaring energy costs could weigh on economic growth and

complicate the Federal Reserve's monetary policy trajectory. In

March, the benchmark S&P 500 posted its biggest monthly

fall in a year.

Short-term Treasury yields slipped on Wednesday, while

interest-rate futures show investors see a 56% chance of a

25-basis-point cut by the end of 2026, according to

LSEG-compiled data.

Before the war erupted, traders had been betting on at least

two 25-basis-point interest rate cuts this year.

Later in the day, investors will parse comments from Fed

policymakers Mary Daly and Christopher Waller, and minutes from

the central bank's March 17-18 meeting.