(Updates prices, adds AI concerns)

* Trump unhappy with latest Iranian proposal, official

says

* Tech stocks stumble as investors focus on AI spending

boom

* BOJ holds rates; Fed, ECB and BoE also to stand pat

this week

By Harry Robertson and Ankur Banerjee

LONDON/SINGAPORE, April 28 (Reuters) - Stocks fell and

oil rose on Tuesday as investors assessed the stalemate in the

Iran conflict and worried the AI boom was losing momentum, while

the dollar climbed.

The U.S. was reviewing Tehran's latest proposal to resolve

the war. A U.S. official said President Donald Trump was unhappy

with the plan as it did not address Iran's nuclear programme.

The two-month-long conflict is at an impasse and energy and

other supplies are still failing to cross through the critical

Strait of Hormuz, pushing oil prices above $110 a barrel on

Tuesday.

Brent crude oil rose 3% to $111.40 a barrel, a

three-week high, while U.S. oil was up 3.8% at $100.

EARNINGS SEASON AND AI IN FOCUS

Oil prices have steadily climbed in recent days as hopes

have ebbed for an imminent peace deal, pushing up bond yields

around the world .

Futures for the U.S. benchmark S&P 500 stock index

fell 0.7% on Tuesday, while those for tech-focused Nasdaq

dropped 1.3%.

"Earnings season has helped markets look through the

disruption, but the longer key oil flows remain constrained, the

greater the risk that higher energy costs begin to bite," said

Matt Britzman, senior equity analyst at Hargreaves Lansdown.

Tech stocks related to OpenAI, such as Oracle and

CoreWeave ( CRWV ), fell in pre-market trading after the Wall

Street Journal reported the company has missed its goals for new

users and revenue in recent months.

Europe's STOXX 600 index dropped 0.5%, with the

tech sector down 1.7% as investors focused on concerns about the

boom in AI spending.

The U.S. S&P 500 hit another record on Monday after

rising for four weeks on optimism over a possible peace deal and

ongoing excitement around AI.

But investors are focusing this week on earnings from U.S.

tech giants Microsoft ( MSFT ), Alphabet, Amazon ( AMZN )

, Meta Platforms ( META ) and Apple ( AAPL ) that will

test the AI-driven rally.

Elsewhere, the dollar index climbed 0.4% as the pound

fell 0.5% and the euro dipped 0.35% .

The dollar has been one of the few safe-haven assets during the

Iran conflict, although it has given up many of its March gains

in the last few weeks.

"The twists and turns of U.S.-Iran peace negotiations

continue to buffet markets," Nick Rees, head of macro research

at Monex Europe, said, adding doubts over the progress of peace

talks had pushed the dollar higher.

BANK OF JAPAN SPLIT ON RATES

The BOJ left short-term rates unchanged on Tuesday at 0.75%,

in the first of several central bank meetings this week that

could provide evidence of the conflict's economic impact.

"The 6-3 vote split and the stronger language on future

policy adjustment suggest the bar for another hike may be

falling," said Charu Chanana, chief investment strategist at

Saxo.

The yen initially strengthened but was last around

0.2% lower at 159.68 per dollar, putting it near 160. A breach

beyond that threshold has markets worried Tokyo might step in to

support the currency.

Japan's Nikkei stock index fell 1% from a record

high hit on Monday.

Global monetary policy is in focus this week, with the U.S.

Federal Reserve, the Bank of England and the European Central

Bank due to announce decisions after the BOJ.

All are expected to keep rates unchanged but market

attention will be on comments from policymakers on pricing

pressure.