* Riyadh to shift away from U.S. over Syria - source
* Wide consequences for Saudi policy, including oil sales
* U.S. crude stockpiles grow more than expected - EIA
* Coming up: U.S. API industry stock data at 2030 GMT
LONDON, Oct 22 (Reuters) - Brent crude oil rose above $110 per barrel on Tuesday, pulling its premium above U.S. light crude to the widest in six months, after news of a deterioration in relations between the United States and key OPEC oil producer Saudi Arabia.
A source close to Saudi policy said Riyadh would make a "major shift" in dealings with the United States in protest at Washington's perceived inaction over the Syria war and its overtures to Iran.
The source suggested the planned change in ties between the energy superpower and its traditional U.S. ally would have wide-ranging consequences, including on arms purchases and oil sales.
Saudi Arabia is the most important oil producer in the Middle East, pumping over 10 million barrels per day, and plays a key role in balancing oil markets to keep prices stable.
Analysts say any impact on Saudi oil sales policy could have a dramatic impact on prices.
Brent for December rose $1.30 per barrel to a high of $110.94 before slipping back to around $110.50 by 1440 GMT.
U.S. crude futures, meanwhile, fell after delayed government oil data showed higher U.S. crude inventories.
U.S. crude futures for November, which were due to expire at the end of trade on Tuesday, fell below $99, their lowest since early July, before recovering to trade unchanged at around $99.20 per barrel.
Crude inventories in the world's top oil consumer rose in the week to Oct. 11 by 4 million barrels to 374.5 million, the U.S. Energy Information Administration (EIA) said, well above an increase of 2.2 million forecast in a poll of analysts.
Inventories at Cushing, Oklahoma, the delivery hub for the U.S. oil benchmark, rose by 366,000 barrels to 32.99 million as pipeline bottlenecks eased, after shedding 17 million barrels since June 28.
Seasonal refinery maintenance and shifting pipeline flows around Cushing helped reverse a long decline in stockpiles.
Traders are now betting on a near-term surplus of inventories in the United States, at least until refineries begin to increase processing again.
A Reuters poll of analysts said U.S. commercial crude oil inventories were forecast to have increased further last week.
The EIA will return to its normal schedule this week, reporting on Wednesday at 10:30 a.m. (1430 GMT). The American Petroleum Institute (API) will release its data on Tuesday at 4:30 p.m. EDT (2030 GMT).
"Refining maintenance has eaten into demand for U.S. crude, helping build stocks," said Carsten Fritsch, senior oil and commodities analyst at Commerzbank in Frankfurt.
Brent was also supported by a belief the Federal Reserve might delay tightening monetary policy until next year, which would remove some of the worries about demand in the U.S. economy and beyond.