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* Futures up: Dow 0.4%, S&P 500 0.6%, Nasdaq 1.4%

July 21 (Reuters) - U.S. stock index futures rose on Tuesday

as renewed mediation efforts in the Middle East lifted

sentiment, while investors looked ahead to corporate earnings

that could prove pivotal for the AI market as it navigates

ongoing pressures.

Markets were weighing mixed signals from the U.S.-Iran

conflict after a senior Iranian official told Reuters on Monday

that Tehran had received a proposal from mediators for a 10-day

ceasefire.

Tensions in the nearly five-month-long war have widened in

recent days, with Yemen's Iran-aligned Houthis saying they would

impose a naval blockade on Saudi Arabia, raising risks to global

energy supplies and trade beyond the Gulf.

Yet Brent crude futures pulled back from a one-month

high, as investors latched on to hopes of a resolution, though

markets have seen similar optimism fade several times since the

war began.

The decline in oil prices helped lift equities, with

recently battered semiconductor stocks leading premarket gains.

The iShares Semiconductor ETF rose 3.8%.

"While shipping confidence and oil production may take

longer than expected to be fully restored, we expect limited

pass-through to core inflation, keeping central banks from

tightening aggressively," said Mark Haefele, chief investment

officer at UBS Global Wealth Management.

"This means earnings growth should remain a key driver of

the equity market."

Lately, chip stocks have come under heavy pressure, as

investors question whether this year's powerful rally in the

sector has gone too far.

The Philadelphia SE Semiconductor Index ended Friday

more than 20% below its late-June record high, confirming a

bear-market decline, though the index remains up about 66% for

the year.

At 5:19 a.m. ET, Dow E-minis were up 189 points, or

0.36%, and S&P 500 E-minis were up 43 points, or 0.57%.

Nasdaq 100 E-minis were up 415.75 points, or 1.44%.

Recent volatility in chip stocks, which later spread to the

broader markets, pushed Wall Street's main indexes to three

straight sessions of losses despite an upbeat start to the

second-quarter earnings season.

Investor focus this week will turn to results from Alphabet

and Intel ( INTC ), which could help determine whether

the AI trade has further room to run amid elevated profit

expectations.

Adding to the uncertainty, President Donald Trump on Monday

unveiled 50% tariffs on a wide range of imports from Canada,

opening a potential new front in the global trade war. The U.S.

administration said the move was in response to Canada's

treatment of American-made cars, alcohol and dairy goods.

Among individual stocks, Nebius ( NBIS ) rose 7.7% after

Nvidia ( NVDA ) disclosed a 9.3% passive stake in the AI cloud

firm.