Crude oil prices started the week on the front foot on Monday, holding near the five-month highs seen last week, amid optimism over the outlook for global supply and demand.

U.S. West Texas Intermediate (WTI) crude futures tacked on 22 cents, or around 0.5%, to $50.66 a barrel by 4:15AM ET (0815GMT), not far from a five-month high of $50.88 touched last Thursday.

Meanwhile, Brent crude futures, the benchmark for oil prices outside the U.S., was up 3 cents, or less than 0.1%, to $55.65 a barrel. It traded as high as $55.99 intraday Thursday, a level last seen since May.

WTI crude saw a rise of 5.1% last week, while Brent ended about 3.4% higher for the week, with both benchmarks marking the strongest weekly gains since the week ended July 28.

Sentiment in the oil market was boosted by last week's bullish demand forecasts from the Organization of the Petroleum Exporting Countries and the International Energy Agency.

The data also showed that global oil production fell last month for the first time since March, boosting optimism that the market is rebalancing.

In addition, U.S. refineries along the Gulf Coast have been reporting a much better recovery than expected after being shut due to hurricanes Harvey and Irma, which battered the region over the past three weeks.

U.S. energy firms cut seven oil rigs in the week to Sept. 15, bringing the total to 749, the fewest since June, energy services company Baker Hughes said on Friday.

Oil traders now looked ahead to a meeting Friday between the Organization of the Petroleum Exporting Countries and other producers regarding a possible extension of production caps.

OPEC and its allies are discussing extending by more than three months the oil production cuts that expire in March 2018, potentially prolonging them well into the second half of next year, according to people familiar with the matter.

OPEC and other producers, including Russia, have agreed to reduce output by about 1.8 million barrels per day until next March in a bid to reduce global oil inventories and support oil prices.

Elsewhere, gasoline futures gained half a cent, or 0.4%, to $1.667 a gallon, whilenatural gas futures added 4.3 cents, or 1.4%, to $3.067 per million British thermal units.