Oil prices slipped, while gasoline futures soared to their highest since July 2015, as energy markets digested the impact of Hurricane Harvey on the U.S. Gulf Coast.

Harvey came ashore over the weekend as the most powerful hurricane to hit Texas in more than 50 years, killing at least two people, causing large-scale flooding, and forcing the closure of Houston port as well as several refineries.

Texas is home to 5.6 million barrels of refining capacity per day. Over 2 million barrels per day (bpd) of refining capacity were estimated to be offline as a result of the storm.

Although the full extent of the storm's damage is not yet clear, some analysts said the impact would be felt globally and affect energy markets for weeks.

British officials arrived in Brussels to begin a third round of Article 50 negotiations with the European Union (EU).

Chief Brexit negotiators, Britain's David Davis and the EU's Michel Barnier, will meet at 15:00 GMT before more talks on Tuesday and Wednesday. A news conference is due on Thursday, according to a schedule published by Brussels.

Earlier this year, Barnier said that the third round of talks must be about "clarification" in terms of where the UK stands on certain issues, including financial settlements.

The UK however is expected to urge the EU to show imagination and flexibility in the upcoming talks, and focus on the two regions' post-Brexit ties, rather than just on the divorce settlement.

The Euro touched fresh 2.5 year highs against the dollar after European Central Bank President Mario Draghi held off talking about the recent strength of the currency in a speech at the Jackson Hole economic symposium.

Draghi also avoided giving new clues as to when the ECB might wind down its stimulus programs but acknowledged that the euro zone’s economic recovery is gaining ground.

Meanwhile, the U.S. dollar sank to its lowest in more than a year after a speech by Federal Reserve Chair Janet Yellen at the same conference made no reference to monetary policy.

The U.S. dollar index, which measures the greenback’s strength against a trade-weighted basket of six major currencies, was at 92.38 after falling as low as 92.30 earlier, the weakest since May 2016.

Global stock markets started the week on the back foot, as investors fretted over the economic impact of Hurricane Harvey, while eying movements in the currency market.

Stock markets across Asia ended mixed, with benchmarks in mainland China and Hong Kong rising, while Seoul and Sydney finished lower. Japan's Nikkei 225 was little changed.

In Europe, shares were weaker in mid-morning trade, with almost all major bourses across the region in negative territory. London's FTSE 100 was closed for a public holiday.

Meanwhile, U.S. stock futures pointed to a softer open on Wall Street later in the day, with the major benchmarks down between 0.1%-and-0.2%.