South Korea was on high alert Thursday for more cyber attacks amid suspicions that North Korea was behind a recent wave of Web site outages in the South and in the United States. The South Korea warned that computer networks of key infrastructure could be targeted. According to AP, the National Intelligence Service said in a statement that it was strengthening cyber security measures for government computer networks, citing a possible new wave of attacks which could target national infrastructure operators like energy, telecommunications and media companies.

Earlier Thursday, the country’s leading computer security company also warned that another wave of attacks was expected in South Korea later in the day.