SINGAPORE, Dec 17 (Reuters) - Asia's middle distillates markets saw a pick-up in spot and window swaps activity on Tuesday, with two more refiners offering January spot cargoes in line with earlier expectations.

SK Energy and Formosa Petrochemical Corp continued their January sales activity, even as some traders were already away from the market for the holidays.

Meanwhile, jet fuel markets took a slight breather, though there were some talks of China's refiners starting their spot discussions for January soon. Further details could not be confirmed immediately.

Refining margins GO10SGCKMc1 slipped slightly below $16 a barrel, reflecting the weakness in both paper and ICE gasoil futures against a backdrop of weaker crude futures.

Cash differentials GO10-SIN-DIF closed the session higher at premiums of 48 cents a barrel, as some buyers were present for January cargoes, with lower-priced offers remaining scant throughout.

Regrade JETREG10SGMc1 discounts narrowed slightly to around 53 cents a barrel, with the general lack of activity in the jet fuel paper markets limiting fluctuations.

SINGAPORE CASH DEALS O/AS

- No deals for both fuels

INVENTORIES

- U.S. crude oil and distillate stockpiles were expected to have fallen last week while gasoline inventories likely rose, a preliminary Reuters poll showed on Monday. EIA/S

REFINERY NEWS REF/OUT

- Shell SHEL.L began restarting the crude distillation unit (CDU) at its 233,702 barrel-per-day (bpd) Norco, Louisiana, refinery, people familiar with plant operations said on Monday.

- HF Sinclair DINO.O said on Monday it had extinguished a fire at its Holly Frontier refinery in Tulsa, Oklahoma, according to local media.

NEWS

- Oil prices nudged lower on Tuesday as China's economic data renewed demand concerns, while investors remained cautious ahead of the U.S. Federal Reserve's interest rate decision. O/R

- Phillips 66 PSX.N said on Monday it would sell its 25% stake in the Gulf Coast Express pipeline in Texas to an affiliate of ArcLight Capital Partners for $865 million, setting the U.S. refiner on course to exceed its asset sale target.

- European automakers are raising prices of petrol cars and readying discounts on electric vehicles as they brace for yet another challenge - tougher emissions rules that threaten to further shrink profits across the struggling industry.

PRICES

(Reporting by Trixie Yap; Editing by Eileen Soreng)

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