By Rae Wee

SINGAPORE, May 26 (Reuters) - Oil prices rose on Tuesday and stocks were mixed as investor optimism over an imminent U.S.-Iran peace deal was tempered by new U.S. strikes in the Middle East.

Iran's top negotiator and its foreign minister were in Doha for talks with Qatar's prime minister on a potential deal with the U.S. to end the war, an official briefed on the visit said, after Washington and Tehran played down hopes for an imminent breakthrough.

The Nikkei newspaper separately reported that both parties were discussing a plan to open the Strait of Hormuz about 30 days after reaching a deal to end hostilities.

But even as the talks proceeded, U.S. forces conducted strikes on Monday in southern Iran against targets including boats attempting to lay mines and missile launch sites, in what they described as defensive actions.

The developments sent Brent futures LCOc1 rising more than 1% in early Asian trade to $97.32 a barrel. U.S. West Texas Intermediate crude CLc1 was up slightly from Monday's last traded price but down 5.5% from Friday's close. There was no settlement on Monday due to the U.S. Memorial Day holiday.

"I'm a bit sceptical... We keep being told there's a deal that's near, but what does the deal look like? That's what's really important. When's the Strait of Hormuz going to open... There's a lot we don't know," said Joseph Capurso, a strategist at Commonwealth Bank of Australia.

Stock markets were mixed, with MSCI's broadest index of Asia-Pacific shares outside Japan .MIAPJ0000PUS advancing 0.8%, while Japan's Nikkei .N225 shed 0.2%.

Nasdaq futures NQc1 trimmed earlier gains to trade 0.9% higher, while S&P 500 futures ESc1 rose 0.68%.

EUROSTOXX 50 futures STXEc1 eased 0.36%, while FTSE futures FFIc1 added 0.4% and DAX futures FDXc1 lost 0.43%.

"The market wants to believe that it's all going to end soon, because the war not ending is quite bad for the world economy. The world economy's had these buffers of running down inventories, but you can't keep running down inventories," said Capurso.

DOLLAR STEADIES

In currencies, the dollar steadied on Tuesday on renewed safe-haven demand, though it remained some distance away from a six-week peak hit last week.

The euro EUR= fell 0.06% to $1.1636, while sterling GBP= eased to $1.3498.

Against the yen, the dollar was flat at 158.95 JPY=.

Bonds were largely steady after a rout last week on worries that higher energy prices for longer would stoke a resurgence in inflation and prompt rate hikes across both developed and emerging markets.

The yield on the two-year U.S. Treasury note US2YT=RR was last little changed at 4.0612%, while the 10-year yield US10YT=RR fell to 4.5024%.

"We are likely to see periodic yield retracements on occasions when geopolitical risks subside, but inflation and fiscal risks are likely to be more sustained," said Eric Robertsen, Standard Chartered's head of global research and chief strategist.

"Commodity supply dislocations will take months to resolve, and fiscal support measures are likely to drive a sustained deterioration in sovereign balance sheets - which will also require increased borrowing in an environment of higher funding costs."

Elsewhere, spot gold XAU= was down 0.5% at $4,545.90 an ounce. GOL/