The U.K. pound fell to a two-week low against the U.S. dollar Friday after fresh polling data showed a narrowing lead for incumbent Prime Minister Theresa May in the final weeks of the country's contentious election campaign.

In the first survey of voters released since the deadly terrorist attack in Manchester earlier this week that killed at least 22 people and injured more than 60 others at the conclusion of an Ariana Grande concert, polling expert YouGov said May's Conservative Party holds only a 5-point lead over their Labour Party rivals, lead by Jeremy Corbyn, down from 9 points last week.  

"It has been a highly unusual few days in an election campaign, arguably unlike any other in history," YouGov said. "There is no way of guessing what will happen in the two weeks to polling day but we will be able to be more confident about how voting intention settles down over the next few days."

The pound was marked 0.5% lower against the dollar at 1.2880 in early European trading after having hit a two-week low of 1.2860 overnight in Asia, the weakest since May 12. The cross rate between the pound and the European single currency, meanwhile, traded at a two-month low of 1.1487.

Friday's losses extended declines for the the currency that were triggered yesterday after data from the Office for National Statistics showed that the pace of growth in Britain's economy -- Europe's second-largest -- slowed to 0.2% in the first three months of the year owing to a pullback in consumer spending and much faster-than-expected inflation.

"Consumer facing industries such as retail and accommodation fell and household spending slowed," the ONS said. "This was partly due to rising prices. Construction and manufacturing also showed little growth, while business services & finance continued to grow strongly."