WASHINGTON - Japanese Self Defense Forces Chief of the Joint Staff Shigeru Iwasaki on Thursday visited the Pentagon, holding a discussion with US Chairman of the Joint Chiefs of Staff Martin Dempsey on the security environment in the Asia-Pacific region and strengthening the alliance as tensions in East China Sea rise.

According to a official visit statement, Dempsey and Iwasaki reaffirmed the "vital nature of the US-Japan Alliance for the security of both countries as well as for the peace, stability, and economic prosperity of the Asia-Pacific region."

They also confirmed to deepen operational cooperation to deal effectively with common security challenges, the statement said.

They also discussed bilateral dynamic defense cooperation and identified ways to strengthen bilateral engagement, including "timely and effective bilateral training, bilateral surveillance and reconnaissance activities, and joint-shared use of facilities."

Recently, Japan has seen tensions rise in its relations with China over the Chinese-owned Diaoyu Islands, and the Japanese forces joined US Marines Tuesday in the western Pacific Ocean for a month-long military drill aimed at tackling the scenario of taking back islands occupied by enemy troops.

During a press briefing, Dempsey said he held conversations with Iwasaki on the drill, noting the cooperation between the two countries may not be limited in the maritime domain.

"One of the purposes of the general's (Iwasaki) visit here is to take what is already a very close mil-to-mil relationship and look for ways that we might continue to expand it," including in maritime, cyber, land and air domain.

"We're not limiting ourselves to the maritime domain," said Dempsey.

Iwasaki echoed the comment, saying cooperation between the two will "not limit only to the region such as East China Sea," but would cover issues such as intelligence, surveillance, and reconnaissance.