South Korea’s police chief on Monday blamed North Korean hackers of sending a large number of spam emails to Seoul’s public organizations last month, South Korea's Yonhap News Agency reported. The latest alleged cyberattack comes amid a series of several such moves by North Korea targeting its neighbor in recent years.

"We are at a stage to be assured that it was committed by a North Korean hacking organization," Kang Sin-myeong, commissioner-general of the National Police Agency, said while announcing the interim report on the probe into the case, Yonhap reported.

The spam emails were disguised as being sent by either the presidential office or the foreign ministry, and the contents were related to North Korea’s recent nuclear test, Yonhap reported.

According to the probe report, the Internet Protocol address used to send the emails was traced to China's northeastern province of Liaoning bordering North Korea. Kang said that the internet network was the same as the one used during a cyberattack on South Korea’s nuclear power operator in 2014.

South Korean police reportedly said that the spam emails were sent from June 2015 to a total of 759 people.

"Looking at the probe results, there is a trace of an intentional and deliberate targeting process that cannot be deemed as a coincidence," Kang said, according to Yonhap.

The police chief reportedly said that the attack did not have any major impact on Seoul’s national security. Two European servers were also involved in sending other spam emails disguised as a notice from a major South Korean portal site, police said. Authorities plan to conduct an international probe into the incident following the links to European servers, Yonhap reported.

North Korea has been accused of conducting several cyberattacks on South Korea and the United States in recent years. However, Pyongyang has denied all allegations of involvement.

In late January, South Korea raised its cyber alert level following a flood of malicious emails presumed to have been originated from North Korea amid heightened tensions between the two Koreas over Pyongyang’s nuclear test earlier that month.

"North Korea has attempted cyberattacks previously to spark public anxiety and hostility against the government," South Korea's Ministry of Science reportedly said, at the time, adding that the series of emails may be part of North Korea's broader provocation, following its claim of successfully conducting a hydrogen bomb test on Jan. 6.