US and Japanese diplomats have agreed to maximize pressure on North Korea in a bid to resolve tensions over its nuclear program, AP reports. US Undersecretary of State John Sullivan met with his Japanese counterpart, Shinsuke Sugiyama on Tuesday. The focus at the State Department is still on diplomacy to solve the problem and eventually denuclearize the Korean Peninsula, according to Sullivan. “We must, however, with our allies in Japan and South Korea and elsewhere, be prepared for the worst should diplomacy fail,” he said. The US must be prepared to defend itself and its allies, the diplomat added.