* U.S. crude output expected to break through 10 mln bpd -IEA
* Crude prices in line for biggest weekly drop since October
* Speculators raise U.S. crude net longs to another record-CFTC
* Brent crude speculators cut net long positions -ICE
* U.S. oil rig count falls by five this week - Baker Hughes (Recasts with settlement prices, CFTC and ICE contract data, adds analyst comment)
By Bryan Sims
Houston, Jan 19 (Reuters) - Oil prices ended down on Friday and broke a four-week winning streak after a rally that had taken benchmarks to three-year highs, as investors sold positions on re-emerging U.S. production concerns.
Brent crude futures fell 70 cents, or 1 percent, to settle at $68.61 a barrel after hitting a session low of $68.28. On Monday, they hit their highest since December 2014 at $70.37.
U.S. West Texas Intermediate (WTI) crude futures settled at $63.37 a barrel, down 58 cents, or 0.9 percent. WTI marked a December-2014 peak of $64.89 a barrel on Tuesday.
On a weekly basis, Brent settled 1.8 percent lower while WTI was down 1.5 percent.
“We had such a meteoric rise in the oil market recently and we were overbought quite a bit. This is the first time we’ve taken a breath,” said Phil Flynn, analyst at Price Futures Group in Chicago.
“The pullback in relationship to the recent run-up is still very modest,” he added.
The International Energy Agency (IEA) said in its monthly report that global oil stocks have tightened substantially, aided by OPEC cuts, demand growth and Venezuelan production hitting near 30-year lows.
But it warned that rapidly increasing production in the United States could threaten market balancing.
“Explosive growth in the U.S. and substantial gains in Canada and Brazil will far outweigh potentially steep declines in Venezuela and Mexico,” the IEA said of 2018 production.
The energy watchdog forecast U.S. supply growth will push its output past 10 million barrels per day (bpd), overtaking Saudi Arabia and rivalling Russia.
U.S. crude oil production C-OUT-T-EIA rose nearly 300,000 bpd to 9.75 million bpd last week, according to government data.
The U.S. oil rig count, an indicator of future production, fell by five this week but at 747, was still much higher than the 551 rigs a year ago, according to General Electric Co’s Baker Hughes energy services firm. RIG-OL-USA-BHI
“The drop in the rig count should place a little bit of doubt about the IEA’s forecast of explosive growth. People are starting to really question the validity of demand,” Flynn said.
Overall, however, oil prices remain well supported, and most analysts do not expect steep declines.
Hedge funds have been increasing long positions steadily on expectations that tightening supply will keep prices buoyant. Money managers raised their net long U.S. crude futures and options positions in New York and London by 40,855 contracts to 541,990 in the week to Jan. 16, a record high, the U.S. Commodity Futures Trading Commission said.
In a separate report, Intercontinental Exchange Inc said speculators trimmed positions in Brent in the week to Jan. 16 from a record the week before, dropping 3,357 contracts to 570,795.
The main price driver has been a production cut by major producers led by the Organization of the Petroleum Exporting Countries (OPEC) and Russia since January last year.
The supply cuts, scheduled to last throughout 2018, were aimed at tightening the market to prop up prices.
Even in the United States, not part of the pact to curb output, crude inventories fell 6.9 million barrels last week to 412.65 million barrels, the lowest seasonal level in three years and below the five-year average marker around 420 million barrels.
Additional reporting by Libby George in London, Henning Gloystein in Singapore and Jane Chung in SEOUL; Editing by Marguerita Choy