Nov. 13 (UPI) -- U.S. Vice President Mike Pence vowed to work toward the complete denuclearization of North Korea and fully enforce sanctions during a joint press conference with Japan's prime minister on Tuesday.

Pence, who is expected to attend the APEC meeting in Papua New Guinea on Saturday instead of President Donald Trump, said the United States stands firmly against countries that threatened freedom and openness in the region, including North Korea, NHK reported.

Pence and Prime Minister Shinzo Abe also pledged to work toward a free and open Indo-Pacific, a reference to a Trump administration policy of U.S. inclusiveness and cooperation with partner countries in Asia. Analysts have said the policy is also a check against growing Chinese ambitions.

Pence told reporters economic sanctions against North Korea will be fully enforced until complete denuclearization, and that there is still a lot of work that needs to be done before embargoes are lifted.

The vice president reiterated Trump's earlier comments on negotiations with North Korea -- and said the president had made it clear time is not a major factor in the implementation of the agreement reached at the June summit in Singapore.

Trump said last week a second summit with Kim Jong Un could take place in early 2019, but he also said there was "no rush" in negotiations with North Korea.

Abe said Japan's alliance with the United States is firm and said the two sides agreed United Nations Security Council sanctions resolutions must be maintained for the complete denuclearization of North Korea.

While Tokyo and Washington have coordinated on North Korea sanctions, the two countries have some remaining disputes over trade.

Voice of America reported Tuesday Pence complained about Japanese trade regulations at the press conference.

"American products and services too often face barriers to compete fairly in Japanese markets," the vice president said.

The "best opportunity for free, fair and reciprocal trade will come in a bilateral trade agreement."

Japan has favored the multilateral Trans-Pacific Partnership over a bilateral deal with the United States.