UPDATE 1-UK's Johnston Press says new data privacy rules hitting online ads

(Adds details on GDPR, company comments)

June 5 (Reuters) - British regional newspaper publisher Johnston Press Plc said European changes to data privacy rules had hit its online advertising revenue, threatening the one area of strong growth for the industry.

Johnston Press, which publishes a string of local newspapers around the country including The Scotsman and The Yorkshire Post, said trading had been "extremely challenging" in the first five months of the year, with revenue down 9 percent.

The group maintained its expectations for the full year however, helped by a strong performance from its i newspaper, a national title sold at a low cost and once the sister paper of the Independent newspaper.

"The trading environment remains extremely challenging, exacerbated in recent months by uncertainty around future paper costs and the impact of GDPR on digital advertising revenues," it said.

The General Data Protection Regulation (GDPR) imposes new requirements on how companies collect and process personal information about users in the European Union. That threatens to disrupt online advertising which relies on personal data to send targeted ads to consumers.

"We expect to see continued pressure on revenues in the second half of the year, and a requirement for cost savings," Johnston Press said.

(Reporting By Justin George Varghese in Bengaluru; editing by Kate Holton)