Brent oil edged higher on Tuesday, snapping three days of declines and pushing its premium to slumping U.S. crude back above $18 a barrel, as supportive German economic growth helped counter political turmoil in Greece.

Anticipation that inventory reports will show U.S. crude stocks rose an eighth straight time last week, adding to record stockpiles at Cushing, Oklahoma, helped pressure U.S. crude and increase its price deficit to Brent, brokers and traders said. The approach of the June Brent contract's expiration on W ednesday also helped raise the premium to U.S. June crude to $18.26 a barrel based on settlements.

Brent's premium to U.S. crude pushed above $18 for the first time since April 16, when news of this week's planned reversal of the Seaway crude pipeline broke. The pipeline will allow stockpiles bottlenecked in the U.S. Midwest to be sent to the refinery-rich Gulf Coast. However, the initial capacity after the reversal will be only 150,000 barrels per day, insufficient in the short term to drain much of the Midwest glut, traders said.

Brent June crude rose 67 cents to settle at $112.24 a barrel, recovering from a $110.93 low and reaching $112.67. Brent fell to $110.04 on Monday, after reaching $120.02 on May 1, as OPEC's increased production, rising U.S. inventories and signs of slowing economic growth weighed on prices.

U.S. June crude fell for a third straight session, dropping 80 cents to settle at $93.98 a barrel, but extended losses to $93.06 in post-settlement trading.

Brent and U.S. crude, heating oil and gasoline futures all continued to sport relative strength index (RSI) readings below 30. A reading under 30 suggests oversold conditions to investors who follow technical indicators.

U.S. heating oil futures managed to close slightly higher, while gasoline dipped more than a penny. Both settled under $3 a gallon.

Better-than-forecast German first-quarter GDP data raised hopes that Germany might steer its way through the European debt crisis as the euro zone's economy avoided recession but posted zero growth in the quarter.

News that Greece faces a new election after attempts to form a government collapsed reinforced the possibility that parties opposed to the terms of a European Union bailout could win power.

The Greek political impasse weighed on equities, sent the euro to a four-month low against the dollar and key industrial feedstock copper to its own four-month low.

"The German GDP gave the market a little hope and recent problems at the North Sea Buzzard field and Europe's refineries due back from seasonal maintenance have provided Brent with support," said Andy Lebow, senior vice president for energy futures at Jeffries Bache LLC.

U.S. crude stocks were expected to have risen last week, by 1.7 million barrels, a Reuters survey of analysts showed. Distillate stocks were pegged to be down 600,000 barrels and gasoline stocks to have fallen 500,000 barrels. Crude stockpiles at Cushing, the delivery point for the U.S. light sweet crude contract, were at a record high above 44 million barrels as of May 4.

U.S. gasoline demand increased 4.5 percent last week from the previous week as pump prices fell, MasterCard said in a weekly report, but demand remained down versus a year ago, by 3.6 percent. Increased production from Saudi Arabia, Libya and Iraq has helped cushion global supply as U.S. and European Union sanctions continue to limit Iran's exports ahead of an EU embargo on Iranian barrels set for July.

The U.N. International Atomic Energy Agency and Iran will meet again next week after a "good exchange of views" during two days of talks on Tehran's disputed nuclear program, a senior U.N. official said.

(Additional reporting by Gene Ramos in New York, Julia Payne in London and Jessica Jaganathan in Singapore; Editing by Dale Hudson, Bob Burgdorfer and Sofina Mirza-Reid)