Oil market retreats before Yellen testimony

London - Global oil prices dipped on Tuesday as investors awaited congressional testimony by the US's central bank chief for clues about the state of the world's biggest economy, analysts said.

Brent North Sea for delivery in August sank $1.02 to stand at $105.95 a barrel in London early afternoon deals.

New York's benchmark West Texas Intermediate for August fell 73 cents to $100.18 per barrel from Monday's close.

US Federal Reserve chair Janet Yellen will begin two days of testimony later on Tuesday before congressional committees that will focus on the bank's time-frame for raising benchmark interest rates.

"All eyes are on US Federal Reserve chair Janet Yellen's testimony to the Senate today and to the House Committee tomorrow," said Sucden analyst Myrto Sokou.

She added: "The US dollar continues to hold fairly strong, adding further pressure to the oil market."

French lender Credit Agricole predicted Yellen is likely to hint that the Fed will begin "the rate lift-off in 2015".

However, the she is expected to "emphasise that Fed views on the timing of the lift-off remain contingent on the economic outlook," the bank said in a market commentary.

Oil prices received some support from ongoing turmoil in Libya, which has clouded expectations of a return of the country's long-disrupted crude supplies to the market.

Libya suspended all flights to and from its third city Misrata on Monday, a day after deadly clashes closed the country's main international airport in Tripoli and damaged several planes.

Libya's interim Prime Minister Abdullah al-Thani said earlier this month that authorities had regained control of two export terminals - Ras Lanuf and Al-Sidra - blockaded by rebels demanding autonomy in the country's eastern region.

Crude futures had fallen heavily last week, stoked by the prospect that the ports could add about 500,000 barrels of crude per day to global energy markets.

The North African state's output currently stands at about 320 000 barrels per day, about a fifth of its previous output.