SINGAPORE, March 24 (Reuters) - Asia's diesel cash premiums jumped to a new record, with a physical deal on the trading window surfacing for the first time in more than two weeks, though swap market structures eased slightly.

Some more April spot discussions should surface this week, three trade sources said, with a handful of northeast Asian refiners likely having export availability.

Meanwhile, a large part of India-loading barrels for March were likely to be shipped to Asian offtakers, shiptracking data showed, as buyers here continue to cover their immediate requirements.

Volumes are expected to be more than double from last month for now, some traders say, while India's MRPL resurfaced to sell March spot cargoes after a one-month hiatus.

Refining margins GO10SGCKMc1 eased to its lowest level in a week of $55.5 a barrel.

Cash differentials GO10-SIN-DIF soared to slightly more than $53 a barrel, reflecting the higher deals done and tighter supply expectations going into April and May.

On the jet fuel front, the Abu Dhabi III exited the Strait of Hormuz on March 21 carrying aviation fuel bound for Asia, multiple trade sources said, though further details could not be confirmed.

Supplies have lengthened slightly for the remaining of March and April, given the reverse arbitarge cargoes heading here, two sources said.

Vitol remains the largest buyer for April delivery jet fuel, buying around 764,000 barrels of cargoes since early March, traders' data showed.

Regrade JETREG10SGMc1 eased to its lowest premium in three weeks of slightly below $1 a barrel.

SINGAPORE CASH DEALS O/AS

- No gasoil deal, two jet fuel deals

INVENTORIES

- U.S. crude oil and product stockpiles were predicted to have fallen last week, a preliminary Reuters poll showed on Monday. EIA/S

REFINERY NEWS REF/OUT

- Valero Energy Corp has shut its 380,000-barrel-per-day (bpd) oil refinery in Port Arthur, Texas, following an explosion and fire at a diesel hydrotreater unit, people familiar with the plant operations said on Monday.

NEWS

- Japan will tap joint oil stockpiles held by producing nations in the country by the end of March, Prime Minister Sanae Takaichi said on Tuesday, as Tokyo ramps up emergency measures to offset supply losses from the Middle East.

- Flag carrier Vietnam Airlines plans to cancel 23 flights per week across several domestic routes from April because of looming jet fuel shortages, Vietnam's aviation authority said.

- South Korean President Lee Jae Myung on Tuesday called for a nationwide energy-saving campaign over risks to oil and gas supplies from the Iran war, saying public institutions would cut back on their use of passenger cars.

- Ship-refuelling companies along Africa's coast are seeing a surge in business as more vessels divert around the Cape of Good Hope, with war in the Middle East reshaping global shipping routes and boosting the continent's role as a bunkering hub.

PRICES

(Reporting by Trixie Yap)

((trixie.yap@thomsonreuters.com;))