The US has warned North Korea that it was prepared to meet any eventuality and will take "immediate specific actions" if Pyongyang launches a missile attack against it or its allies.
The US' strong assertion comes days after President Donald Trump pledged to answer further aggression from North Korea with "fire and fury".
Speaking at a news conference jointly addressed by US Defence Secretary James Mattis, Japanese Foreign minister Taro Kono and Defence Minister Itsunori Onodera, Tillerson said the country was prepared to meet any eventuality from the North Koreans, and sought to make it clear that use of the force was not the "preferred pathway" of the US.
"We are prepared, we are prepared militarily, we are prepared with our allies to respond if that is necessary. That (military) is not our preferred pathway. That's been made clear as well," he said.
Defence Secretary Mattis said that the US would take immediate specific actions in the event of a missile launch towards the US or its allies.
"In the event of a missile launch towards the territory of Japan, Guam, the United States, Korea (South Korea), we would take immediate specific actions to take it down," Mattis said.
Responding to a question after the 'two-plus-two' US- Japan talks, Japanese Defence Minister Onodera said that in the event there is an attack on Japan, they will use assets available to them for the missile defence.
"But should different circumstances occur, then we will solidify the relation that we have with the US with close communication. We will defend the country, and that is what we discussed today," he said.
Tillerson said the North Korean regime should engage in diplomatic talks to bring better results, unlike in the past.
"So, our effort is to cause them (North Korean regime) to want to engage in talks, but engage in talks with an understanding that these talks will lead to a different conclusion than talks of the past. We will continue that effort diplomatically, first and foremost," he said.
But, knowing that North Korea sits with a significant capability already within their grasp, I think it is only prudent that they fully understand the consequences, should they make a bad choice for themselves. And, obviously, there are consequences for others as well," Tillerson added.
According to Onodera, North Korea has plans to launch ballistic missiles to the waters close to Guam. It is also advancing on their efforts to launch ICBM-class ballistic missiles, miniaturising nuclear weapons to warheads.
"So for this threat of North Korea, at this meeting, we agreed to increase the pressure and to strengthen the alliance's capability. The four of us confirmed the importance of the unwavering US commitment to extend the deterrence," he said.
Observing that Japan and South Korea are on the front line against the North Korean threat, Mattis said the US recognises that any confrontation with North Korea would pose an immediate danger to its allies and their populations.
"The US-Japan ministerial meeting is a reminder that each nation gains security in concert with other nations. The international community is speaking with one voice. North Korea must stop its dangerous actions as we work to maintain security and denuclearise the Korean peninsula," he said.
"We are accelerating implementation of the 2015 guidelines for US-Japan defence cooperation and continuing to realign US forces in Japan and Guam. Our militaries are also cooperating in new ways. This includes our emerging cooperation in areas such as space and cyberspace, as well as ballistic missile defence and maritime security," Mattis said.
"Together, we will deter and if necessary defeat any threat. Any initiation of hostilities will be met with an effective and overwhelming response," he added.
Mattis said the US and Japan will demonstrate the strength of their alliance by continuing bilateral activities and by enhancing cooperation with South Korea.
He said that the path of provocations and threats chosen by North Korea was not in the best interests of any nation.
"We call on North Korea to choose a better path than one of provocations and threats. Such a path is not in its own best interests nor in the best interests of any other nation," the Defence Secretary said.