Brent crude declined from the highest closing price in a week on speculation that Crimea’s vote to split from Ukraine is unlikely to lead to a disruption in oil supplies.

Futures declined as much as 1% in London, after climbing on March 14. The U.S. and the European Union warned Russia not to annex Crimea after the referendum, setting the stage for sanctions against the world’s biggest energy producer. Libya’s production fell after protesters closed a pipeline carrying crude from Sharara, the country’s second-largest field, according to state-run National Oil Corp.

“The expectation is for no precipitate action by the West over Ukraine, and that the impact will play out over months and years, which is why the market hasn’t gone up,” Christopher Bellew, a senior broker at Jefferies Bache Ltd. in London, said by e-mail.

Brent for May settlement fell as much as $1.09 to $107.12 a barrel on the London-based ICE Futures Europe exchange, and traded for $107.124 as of 12:58 p.m. local time. The April contract expired on March 14. The European benchmark crude was at a premium of $9.27 to the West Texas Intermediate contract on ICE for the same month.

WTI for April delivery declined 59 cents to $98.30 a barrel in electronic trading on the New York Mercantile Exchange. The contract climbed 69 cents to $98.89 on March 14. The volume of all futures traded was about 2% above the 100-day average.

Ukraine Crisis

Brent advanced 1.1% on March 14, the most in 11 days, before Sunday’s referendum. A total of 95.5% of voters in the Black Sea peninsula backed leaving Ukraine to join Russia, preliminary results show. The Ukrainian government, the EU and the U.S. consider the vote illegal while Russia said it “fully met international norms.”

“With the overwhelming pro-Russian vote in the region clashing with the West’s assertions that the referendum is not valid, expect further geopolitical risk-related support this week,” Mark Pervan, the head of commodity research at Australia & New Zealand Banking Group Ltd., said in a note Monday.

U.S. President Barack Obama has signed an executive order authorizing financial sanctions, allowing Treasury Secretary Jacob J. Lew to take steps that may include freezing assets or blocking American companies or individuals from doing business with Russians, Ukrainians or others deemed a threat to Ukraine’s security. U.K. Foreign Secretary William Hague called the Crimea vote “illegal, unconstitutional and illegitimate.”

Aggressive Moves

“If there are more aggressive moves by Russian troops, we’ll see a reaction in prices,” Richard Mallinson, an analyst at Energy Aspects Ltd. in London, said yesterday. “Markets are watching the situation very closely.”

In Libya, crude output dropped to 230,000 barrels a day from 408,000 barrels a day after the disruption at Sharara, Mohamed Elharari, a spokesman at National Oil, said. Protesters are seeking jobs and development projects for the local community. The nation, a member of the Organization of Petroleum Exporting Countries, holds Africa’s biggest oil reserves.

The U.S. Navy thwarted the first attempt by rebels seeking self-rule in eastern Libya to export crude oil from a port they control. Navy SEAL commandos boarded the Morning Glory, a tanker that sailed on March 11 from the Libyan port of Es Sider with a cargo of crude, the U.S. Defense Department said in an e-mailed statement today.

Expanding U.S. oil supplies and production spurred hedge funds and other speculators to cut record bets on rising West Texas Intermediate crude prices.

Money managers reduced their net-long position by 5.3% in the week ended March 11, the first decline in eight weeks, U.S. Commodity Futures Trading Commission data show. Long positions fell 2.9%  and shorts rose for a third week.