LONDON - World oil prices hit the lowest levels for almost 2.5 months this week as a poor global growth outlook added to concerns over a long-running supply glut.

US benchmark West Texas Intermediate (WTI) struck $43.69 a barrel on Wednesday -- the lowest level since May 10.  On Friday, Brent North Sea crude slid to a near 2.5-month low point at $45.26 a barrel. A rally seen in early July "is tapering off and the markets are starting to feel the effects of a supply glut again", said Alex Wijaya, a trader at CMC Markets.

Crude had risen from near 13-year lows below $30 in February to above $50 in June owing to fires in Canada's key oilfields, unrest in key producer Nigeria and the start of the US driving season.

However, with those issues now fading and dealers fretting over Brexit, prices have softened again.

The US Department of Energy on Wednesday reported that the country's commercial crude stockpiles fell by 2.3 million barrels last week, offsetting a surprise rise in gasoline inventories during the peak demand season for American motor fuel.

"We've seen a little bit of a surprise in how much decline in oil there was," said Bert Melek at TD Securities.

Before the US inventory report, prices had already fallen on renewed strength for the dollar -- making the commodity more expensive for buyers holding weaker currencies. And prices were weighed down by a downbeat forecast from the International Monetary Fund, which lowered its global growth forecasts, citing the impact of Britain's vote to exit the European Union.

The IMF said it expects the world economy to expand 3.1 percent this year, lower than it forecast in April. Slower overall growth would likely dampen the expansion of crude oil demand. In China, which is the world's biggest energy consumer, its premier on Friday said the world could not depend on the country to save it from a Brexit-induced downturn.  "It is impossible to carry all of the burden of the whole world on our shoulders," said Premier Li Keqiang, as he prepared to host a meeting of G20 finance ministers.

China's economic boom of recent decades has seen it become the world's second-largest economy and a key driver of global growth, with a massive stimulus package Beijing launched in 2008 credited with helping ease the pain of the global financial crisis.

But investors worldwide have worried over its slowing expansion, while Britain's referendum last month has heightened risks and instability.

Since Britain voted in favour of exiting the European Union, its economy has faced a "dramatic deterioration" in activity as orders dried up and business investments were canned, key data showed Friday. Private sector business activity, as measured by research group Markit's Purchasing Managers Index (PMI), sank in July to 47.7 points.

It was the lowest level since April 2009 following the global financial crisis, and sparked predictions from some quarters of a painful recession. The preliminary reading compared with 52.4 in June and crucially took the PMI below the boom-or-bust 50 points barrier that signals contraction, Markit said.

"July saw a dramatic deterioration in the economy, with business activity slumping at the fastest rate since the height of the global financial crisis in early-2009," said Markit chief economist Chris Williamson.

And owing to the uncertainty caused by Brexit, the head of Hong Kong's stock exchange this week put on hold a planned link between commodities markets in London and Hong Kong.

Charles Li, chief executive of Hong Kong Exchanges and Clearing (HKEx), wrote in a blog post that before the plan can be taken any further there must be more clarity over the outcome of regulatory talks between Europe and Britain following the shock vote.

In oil trading Friday at around 1615 GMT, WTI for delivery in September was down 84 cents at $43.91 a barrel compared with the close on Thursday.

Brent for September shed 86 cents to $45.34 a barrel.