Delivering a speech on the flight deck of an American aircraft carrier anchored at the naval base in Yokosuka, Kanagawa Prefecture, visiting U.S. Vice President Mike Pence warned Pyongyang not to test the resolve and military capability of the United States, vowing that such a move would be met with “an overwhelming and effective American response.”

“The full range of the United States military capability is dedicated to the protection of Japan. Japan, you are our friend — you are our ally — and on that foundation, we will face the future together,” Pence told the thousands of American and Japanese sailors who packed the deck of the USS Ronald Reagan, which is based in the port city.

“We will defeat any attack, and meet any use of conventional or nuclear weapons with an overwhelming and effective American response,” he said in the speech, which was livestreamed on the White House website.

“The United States of America will always seek peace but under President (Donald) Trump, the shield stands guard and the sword stands ready,” he said.

Pence came to Japan on the second leg of his 10-day Asian tour amid growing tensions over Pyongyang’s threat to conduct its sixth nuclear test at any time.

Another atomic test would further advance Pyongyang’s efforts to develop a small enough nuclear warhead that could be mounted on top of a ballistic missile.

North Korea is also trying to develop an intercontinental ballistic missile that can hit the continental U.S. If it ever succeeded, this would pose a grave threat to the United States and its allies.

The USS Ronald Reagan is the U.S. Navy’s only forward-deployed aircraft carrier and a visible symbol of the U.S. power projection in the Asia-Pacific region.

The carrier, however, is undergoing maintenance works and is not expected to depart before May, according to Stars and Stripes, a U.S. newspaper which serves the military community.

Pence chose the ship’s deck as the venue to once again emphasize Washington’s commitment to the Japan-U.S. military alliance based on the 1960 bilateral security treaty.

“You here, on the deck of this great ship, are the physical manifestation of that alliance,” Pence said.

“The U.S. will strengthen its presence in the Asia-Pacific. Japan will assume a larger role and responsibility in our alliance in the years ahead.

“Both of our nations will continue to expand our cooperation for our common defense.”

Pence’s visit to Tokyo was originally designed to focus on trade talks with Japan, and he and Deputy Prime Minister Taro Aso on Tuesday set up a dialogue framework over economic issues.

But global attention has instead shifted to what kind of message Pence would deliver to a recalcitrant North Korea in Tokyo.

“Make no mistake — under President Trump, the U.S. will be strong, stronger than ever before,” the vice president said.

“When America is strong, the world is safe,” he added.

Pence also reaffirmed that the Japan-U.S. bilateral security treaty would be applied to the disputed Senkaku Islands in the East China Sea, which are claimed by both China and Taiwan. The Japanese-administered islets are known as the Diaoyus in China and Tiaoyutais in Taiwan.

“Under President Trump, the U.S. commitment to Article 5 of our security treaty is unwavering, and the treaty covers all of the territories administered by Japan, including the Senkaku Islands,” Pence said.

Claiming sovereign power over the uninhabited islets, Beijing regularly dispatches government ships to the area — moves that have unnerved Tokyo.

Article 5 obliges the U.S. to jointly defend areas administered by Japan, and U.S. top officials have repeatedly affirmed this obligation to ease public concerns among Japanese over the potential for military clashes between Japan and China.