Another South Korean government-run online service suffered an outage Friday, marking the fourth such failure within the past week.

A website and mobile applications providing online ID services went down, according to the Ministry of Interior and Safety.

Friday’s breakdown in the government’s e-ID service comes a day after a website run by the Ministry of Economy and Finance-affiliated Public Procurement Service crashed on Thursday. The PPS website used by all government institutions for making transactions froze for about an hour before it could be restored.

The National Intelligence Service suggested the possibility of an attack, saying that at the time of the failure, an unknown agent with a foreign Internet Protocol address had tried to access the PPS web server.

“Some concentrated attacks targeting the website have been found,” it said in a release late Thursday, adding that it does not yet have the details of who was behind the attack, or what they were seeking.

A week prior on Nov. 17, an online platform for processing civil complaints and an internal portal used by government workers for day-to-day operations broke down for at least a full day.

The Ministry of the Interior and Safety, overseeing the government networks, explained in a briefing over the weekend that a “glitch” appeared to be behind the failures. The NIS then said it was looking at “all possible scenarios, including cyberattacks.”

Neither the Interior Ministry nor the NIS has yet provided an additional explanation or exact cause for the outages.

Experts say the series of outages calls for a full evaluation of the all government systems to verify their security from the latest cyberthreats.

Kwon Hun-yeong, a cybersecurity professor at Korea University, told The Korea Herald that “a full-scale assessment is necessary" to determine "if the legacy government systems are up to date on the latest computing environment, and fit to continue to mange our information resources.”