Washington, Jumada II 5, 1438, Mar 4, 2017, SPA -- Former US president Barack Obama undertook a series of cyberattacks against North Korea's missile programme, the New York Times reported Saturday according to dpa. Obama warned his successor Donald Trump that the North Korean nuclear programme would be his biggest international challenge, and Trump's advisors are now weighing options that include continuing the cyberattacks. Obama began the attacks in 2014 after concluding anti-missile systems were not enough to protect the United States and chose instead to target missiles before test launches, the report said. Details of the programme were not released at the request of national security officials, the newspaper said. After the US implemented the strategy, several missile launches failed or veered off course. The UN tightened sanctions on North Korea in November, two months after it carried out its fifth nuclear test, in a bid to prevent it from developing nuclear weapons. --SPA 01:53 LOCAL TIME 22:53 GMT www.spa.gov.sa/w345828