* Brent stays near $75 on worries U.S. may exit nuclear deal
* Dollar surges to new 2018 high on U.S. growth
* Resilient tech sector underpins world shares
* Italian shares, bonds selloff on election uncertainty
* Dollar keeps up pressure on emerging markets (Updates throughout, adds quote on Italy, emerging markets)
By Sujata Rao
LONDON, May 8 (Reuters) - Oil prices eased on Tuesday from 3-1/2-year highs they hit on worries the United States may be set to pull out of a key nuclear accord with Iran, but robust tech sector gains in Asia helped support world stocks near one-week highs.
U.S. President Donald Trump will announce at 1800 GMT whether Washington will withdraw from a deal that eased economic sanctions on Iran in exchange for Tehran limiting its nuclear programme. A decision to leave the accord could give another boost to this year's 13 percent oil rally, by constraining Iranian crude exports.
Brent futures nevertheless eased one percent after hitting new highs above $75 a barrel and MSCI's world equity index hovered around flat after two days of gains, having touched one-week highs in the previous session.
"(Trump's decision) has been so well covered, it's probably all in the price by now. And most recent commentary seems to be that after all the bluster, he may only partially withdraw from the deal," said Frances Hudson, global thematic strategist at Aberdeen Standard Investments.
Hudson noted that oil prices had bucked the recent rise in the dollar - usually the two are inversely correlated - suggesting investors remained optimistic about the world economy and hence future demand for crude.
"It's telling you that people are still in glass-half-full mode as far as the economy is concerned," Hudson said.
Downplaying concerns that oil's rise could stoke inflation and dent company profits, she added: "I don't think energy costs for many companies these days are a big enough proportion of their cost base, especially for tech and service sector shares."
Wall Street was lifted on Monday by a strong rally in Apple shares to new record highs following forecast-beating results last week and billionaire Warren Buffett's decision to increase his stake in the firm.
Nearly 80 percent of the S&P 500 companies which have reported first quarter earnings have topped profit estimates, according to Thomson Reuters.
MSCI's global tech index closed Monday at six-week highs . That helped lift emerging Asian shares by 0.5 percent and Japanese equities by 0.2 percent .
Momentum fizzled in Europe, however, with a pan-European equity benchmark and European tech down 0.2 percent . Futures for S&P500, Dow Jones and Nasdaq also slipped about 0.2 percent, signalling Wall Street weakness .
Italian shares were the day's worst performers, slipping 1.5 percent as chances grew of new elections following an inconclusive March 4 vote.
Italian 10-year bond yields rose almost nine basis points to end-March highs.
"It's not a good day for Italian assets. Markets are starting to feel the pressure of elections," said Carlo Franchini, head of institutional clients at Italy's Banca Ifigest.
Italy's fragile economic recovery was at risk, he added.
Countering this was good news from China, where April exports and imports beat forecasts. Trade tensions between China and the United States also seem to have abated slightly, with talks resuming next week.
Mainland Chinese shares rose 1.3 percent.
On currencies, the prospect of solid U.S. growth propelled the dollar to a new 2018 high
Expectations of further rises in U.S. interest rates are forcing investors to buy back dollars they sold earlier this year on worries about Trump's protectionist policies.
"For the foreseeable future attractive interest rates at favourable risk conditions will only be on offer in the United States," Commerzbank said, referring to the fading likelihood of near-term policy tightening in Europe and Japan.
The euro fell 0.3 percent against the dollar to $1.1977 , the lowest since end-December.
Dollar gains have rippled through forex markets in recent days, forcing investors to unwind some of this year's best performing trades - emerging markets.
A sovereign emerging dollar debt index saw spreads over Treasuries at the widest since early-2017, while many currencies touched multi-month lows.
The Turkish lira has plumbed successive record lows, while Argentina was forced last week to raise interest rates to 40 percent to stem peso bleeding
Tech-heavy emerging stocks rose on the day but are down 2 percent this month
"For a few months this year we saw the dollar fall and that was a strong driver ... now that the tide has turned, things look different," said Cristian Maggio, a strategist at TD Securities.
Additional reporting by Hideyuki Sano in Tokyo and Andrew Galbraith in Shanghai; Editing by Catherine Evans