HSBC Holdings Plc said its U.K. online banking continues to be affected by a cyber attack that started earlier on Friday, the second time the bank’s online services have been disrupted in Britain this month.

“Internet and mobile services have partially recovered, and we continue to work to restore a full service,” U.K. Chief Operating Officer John Hackett said in an e-mail. “We are continuing to experience attempted denial of service attacks and we are closely monitoring the situation with the authorities.”

The denial of service attack, which aims to cripple an online system by flooding it with traffic, was “successfully defended,” the bank had said in a previous statement. Customers had taken to Twitter, saying they were unable to access their personal and business accounts on the final business day of the month, when British salaries are typically paid.

British banks have been hurt by a string of outages, some attributed to obsolete software and others to malicious activity by hackers, prompting lawmakers to call for more spending on technology and closer supervision of computer systems by board members.

Earlier this month, HSBC’s personal and business customers were unable to access their online or mobile banking services for three days, following a computer glitch in August that left 275,000 business payments delayed. A payments outage at RBS in June affected 600,000 credit and direct-debit transactions, only seven months after the regulator fined the bank 56 million pounds ($80 million) over previous computer failures.