TOKYO (Reuters) – The top U.S. general restated Washington’s “ironclad commitment” to the security of its close Asian ally, Japan, on Friday amid regional tensions over North Korea, telling his counterpart in Tokyo that “an attack on one is an attack on both of us”.

Fears about North Korea’s missile and nuclear weapons programs have grown in recent weeks. Pyongyang has said it was considering plans to fire missiles over Japan toward the U.S. Pacific territory of Guam, although North Korean leader Kim Jong Un appears to have delayed the decision.

U.S. Defense Secretary Jim Mattis, Secretary of State Rex Tillerson and their Japanese counterparts agreed at a meeting in Washington on Thursday to work more closely on North Korea.

“The most important thing (the ministers’ meeting) did was reaffirm the primacy of our bilateral relationship here in Asia-Pacific,” U.S. Joint Chiefs of Staff Chairman Joseph Dunford said at the start of a meeting with the Chief of Staff of Japan’s Self-Defence Forces, Admiral Katsutoshi Kawano.

“This is a very important time for security in the region and of course we are mostly focused on the threat coming out of North Korea,” Dunford said. “I think we have made it clear to North Korea and anyone else in the region that an attack on one is an attack on both of us.”

Tillerson said in Washington the United States wanted dialogue with Pyongyang, but only if it were meaningful.

“Our effort is to cause them 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,” he said.

In 2005, North Korea reached an agreement with six countries to suspend its nuclear program in return for diplomatic rewards and energy assistance but the deal later collapsed.

Tensions have risen after North Korea conducted two missile tests in July which, like its five atomic bomb tests, were carried out in defiance of international pressure and United Nations resolutions.

U.S. President Donald Trump has vowed not to allow North Korea to develop nuclear missiles that could hit the U.S. mainland but Pyongyang sees its nuclear arsenal as protection against Washington and its partners in Asia.

The new U.S. Ambassador to Japan, William Hagerty, said he had arrived at a difficult time and the United States wanted to work with Japan to “calm the rhetoric” over North Korea.

“Our alliance is rock solid, in fact in my personal view this is the greatest alliance on earth,” he said as he met Prime Minister Shinzo Abe on Friday.

“FIRE AND FURY”

Dunford said on Thursday the United States and South Korea would go ahead with joint military drills next week despite pressure from North Korea and its main ally, China, to halt the contentious exercises that Pyongyang routinely describes as preparation for war.

The Pentagon said on Friday the joint exercise, dubbed Ulchi Freedom Guardian, would start on Aug. 21 and involve about 17,500 U.S. service members as well as troops from Australia, Canada, Colombia, New Zealand, the Netherlands and Britain.

North Korea has fired missiles and taken other steps in response to the war games in the past.

Trump warned North Korea last week it would face “fire and fury” if it threatened the United States, prompting North Korea to say it was considering plans to fire missiles towards Guam.

Both sides have since tempered their rhetoric but with North Korea’s military capabilities growing, Japan has been looking to strengthen its defenses.

The Japanese defense ministry wants to introduce a land-based missile defense system called “Aegis Ashore” to address North Korea’s missile threats and has decided to seek funding in the next fiscal year to cover the system design costs, a Japanese defense official told Reuters. READ MORE