LONDON (Reuters) - No one can be complacent about the potential threat posed by the missiles being developed by North Korea, British Foreign Secretary Boris Johnson said on Tuesday. In an interview with the BBC on Monday, North Korea’s Vice Foreign Minister Han Song-Ryol said Pyongyang would continue to test missiles on a “weekly, monthly and yearly basis”. “The regime is now developing intercontinental ballistic missiles which would be capable of delivering a nuclear strike on the mainland United States. These weapons have not yet been fully tested but no one can be complacent about the potential threat they pose,” Johnson told parliament. Johnson also said he had spoken to his Chinese counterpart on Monday and urged him to use Beijing’s influence to restrain North Korea. 