Japan and the United States unveiled a “historic transition” in defense ties on Monday during Prime Minister Shinzo Abe's visit to Washington. The new revisions, which are the first in 18 years to the rules that govern defense ties between the two nations, come at a time of heightened Chinese belligerence in the South China Sea region, and a growing threat from North Korea.

“The guidelines that we have worked on that have been announced today will enhance Japan's security, deter threats and contribution to regional peace and stability,” U.S. Secretary of State John Kerry said, at a press conference on Monday. The revised guidelines strengthen Japan’s role in global military cooperation, ranging from defense against ballistic missiles, cyber and space attacks, as well as maritime security, in both the Asia-Pacific region as well as across the globe.

The amended guidelines, which also allow Japan to come to the aid of U.S. forces and respond to attacks on any other country, come a year after Abe's government approved a reinterpretation of the country’s constitution. Under Article 9 of Japan’s constitution, which came into effect after World War II, Japan renounced war “as a sovereign right of the nation.” However, in July last year, in a dramatic policy shift from its post-war pacifism, Japan ended the ban on exercising “collective self-defense” and aiding an ally under attack. Under its revised constitution, Japan can shoot down a missile headed toward the U.S. even if Japan itself is not under attack, something that was previously prohibited.

“The new guidelines reflect both the enhancement of solidarity and the expansion of cooperation between Japan and the United States,” Japanese Foreign Minister Fumio Kishida, said, at the press conference. “Japan, in close cooperation with the United States, will continue to contribute even more proactively to ensuring peace, stability and prosperity of not only Japan but the Asia-Pacific region and the international community.”

At the press conference, Kerry also reaffirmed America’s “ironclad” commitment to Japan’s security, including over the issue of a disputed cluster of islands -- known as Senkaku in Japan and Diaoyu in China.

“We reject any suggestion that freedom of navigation, overflight and other unlawful uses of the sea and airspace are privileges granted by big states to small ones subject to the whim and fancy of a big state,” Kerry said, in an apparent reference to China’s claims over these islands.

The announcements came at the beginning of Abe's week-long visit to the U.S.