Crude oil futures fell for a third session, dropping as low as $44.75 a barrel on speculation that increased Iraqi shipments will help meet global needs.

Oil flows from southern Iraq to the Basra and Khor al-Amaya export terminals in the Persian Gulf have doubled from a week ago, and oil began flowing from northern fields through a pipeline to Turkey, according to shipping agents.

American and Iraqi forces in Najaf attacked Shiite cleric Moqtada al-Sadr’s militia, which has targeted oil facilities.

“There is such crisis fatigue,” said the president of Strategic Energy & Economic Research in Winchester, Mass., Michael Lynch. “We have yet to experience all the terrible things that we feared would occur. Al-Sadr’s forces have left the Iraqi oil industry alone during the past week.”

Crude oil for October delivery was down 80 cents, or 1.7%, at $45.25 a barrel at the 2:30 p.m. close of trading on the New York Mercantile Exchange. Prices reached $49.40 a barrel on Friday, the highest since oil began trading in New York in 1983. Futures were 43% higher than a year earlier.

In London, the October Brent crude oil futures contract was down 71 cents, or 1.7%, at $42.32 a barrel on the International Petroleum Exchange. Brent was 42% higher than a year earlier.

“Without any news from the Middle East or supply side we should remain around current levels, but if there is any news about losing supply we should see the price go back up to $50,” said the head of commodities economics research at Societe Generale in Paris, Frederic Lasserre.

British forces clashed with Shiite Muslim militia in the southern Iraqi city of Basra, the region from which Iraq exports almost all its oil. As many as 500 militiamen connected with al-Sadr are in the streets of Basra, and British forces have “engaged” with them during the last 24 hours, Captain Donald Francis said by telephone from Basra.

Iraq’s oil exports through its Persian Gulf terminals were halved the past two weeks as fighting in Najaf and other sites escalated. They have increased to normal levels of about 2 million barrels a day since the weekend. Violence in southern Iraq had led to attacks on the South Oil Co., which directs Iraq’s production in the region.

Militants have repeatedly targeted the pipeline that connects Iraq’s northern fields near Kirkuk with the Turkish Mediterranean port of Ceyhan, stopping the flow of crude oil.

Pumping resumed to Ceyhan at midnight on Friday, said the shipping agents, who declined to be identified. Iraq last exported crude from the terminal in May, when it sold about 7.6 million barrels of oil. There is no timetable yet for the next sale of Iraqi oil from Ceyhan.

“The oil is flowing up north and to Basra in the south,” said a broker with Fimat USA Inc. in New York, Michael Fitzpatrick. “It also looks like we could be looking at the destruction of the Mahdi Army at any minute. All of these changes have to be looked at as positive for oil supplies.”

Iraq was the sixth-largest supplier of crude oil to America in May, accounting for 6.5% of the total, according to Energy Department figures. Iraq has the world’s third-biggest proven oil reserves, according to a report by BP Plc.

Oil prices have rallied this year as expanding economies boosted demand in America and China, which account for a third of global crude oil consumption, according to the International Energy Agency.

Daily demand will rise 2.3% worldwide during the fourth quarter to 83.9 million barrels from a year earlier, the agency said earlier this month.

“I have been a promoter of the idea that there is a synchronized boom out there led by Asia and the United States,” said the chief investment strategist at Prudential Equity Group Inc. in New York, Edward Yardeni. “I think there is a threat to that globalized boom with oil prices at $50.”

Hedge-fund managers and other large speculators last week increased their net-long positions in crude-oil futures and options, according to U.S. Commodity Futures Trading Commission data.

Speculative long positions, or bets prices will rise, outnumbered short positions by the equivalent of 82,794 futures contracts as of Tuesday, the highest since the first week of June, according to a weekly report from the commission.

“The returns on oil futures are looking less appealing” this week, Mr. Lynch said. “Speculators are probably switching to other markets that offer a better return.”