The U.S. Pentagon chief Mark Esper met Japanese Prime Minister Shinzo Abe on Wednesday for the first time since taking office last month, and the two discussed Japan-U.S. alliance and the recent missile launches by the Democratic People's Republic of Korea (DPRK). 

Abe said the Japan-US alliance is stronger than ever before. He said he hopes to further strengthen the alliance and continue the two countries' cooperation to realize a free and open Indo-Pacific region, reported NHK. 

Esper said the bilateral alliance is ironclad and critical to a free, open and secure Indo-Pacific. 

The Pentagon chief said that the DPRK remains a great concern and thanked Japan for its assistance in enforcing UN Security Council resolutions imposing sanctions on Pyongyang. 

He added that the U.S. is committed to the goal of the complete, verifiable and irreversible denuclearization of the DPRK. 

Esper will also meet his Japanese counterpart Takeshi Iwaya later in the day.

Esper, a Gulf War veteran and former executive at defense contractor Raytheon Co, became Pentagon chief on July 23, filling a seven-month void left by the resignation of his predecessor Jim Mattis. 

He is on a tour of the Asia-Pacific region that includes Australia, New Zealand, Mongolia and South Korea. On Friday, he is slated to meet South Korean Defense Minister Jeong Kyeong Doo in Seoul. 

(With input from AFP)