Prime Minister Shinzo Abe will urge U.S. President Donald Trump to dismiss Pyongyang’s assertion that the issue of Japanese nationals abducted decades ago has been resolved when the president meets with North Korean leader Kim Jong Un, government sources said Monday.

Abe will meet with Trump in Washington on Thursday, before the U.S. leader’s unprecedented summit with the North Korean leader scheduled for June 12 in Singapore.

The White House said Monday that the summit — the first between a sitting American president and a North Korean leader — will begin at 9 a.m. in the city-state. Other details of the summit remain unclear.

The prime minister is also planning to ask Trump to convey to Kim that Japan would consider negotiating the normalization of ties and the extension of economic cooperation based on a 2002 bilateral declaration, if progress is made on the long-standing abduction issue, the sources said.

In 2002, then-Prime Minister Junichiro Koizumi and the late North Korean leader Kim Jong Il signed a joint declaration in which both sides agreed that Japan would provide economic cooperation after the normalization of diplomatic ties.

Abe will also seek to confirm the importance of maintaining international sanctions on North Korea, after Trump said Friday he did not want to use the term “maximum pressure,” the sources said.

Trump made the remark after meeting with Kim Jong Un’s right-hand man, former North Korean spy chief Kim Yong Chol, at the White House.

The White House said Monday that the U.S. will continue to apply pressure to the North to relinquish its nuclear weapons and ballistic missiles.

“As the president stated, we have sanctions on. They’re very powerful, and we would not take those sanctions off unless North Korea denuclearized,” White House press secretary Sarah Huckabee Sanders said, in an apparent effort to ease concerns in Tokyo and among other U.S. allies that Trump’s remarks could weaken U.S. and United Nations sanctions on the nuclear-armed North.

“Our policy hasn’t changed,” she said. “Our focus will continue to be on denuclearization.”

Also Monday, a group of seven leading U.S. Senate Democrats, including Senate Minority Leader Chuck Schumer, struck a surprisingly hard-line tone in a letter sent to Trump. That letter urged him to seek the complete, verifiable, and irreversible dismantlement of not only the North’s nuclear arsenal, but also the elimination of its chemical and biological weapons cache and its uranium and plutonium enrichment process before any sanctions relief.

Under the “maximum pressure” campaign, the United States has heaped some of the most stringent sanctions ever on the Kim regime. Trump has boasted that these sanctions were key to bringing the North to the negotiating table, though it is unclear if they played much of a role after Pyongyang announced in late November and in January that it had completed its state nuclear force.

In a nod to Seoul and Tokyo, the letter also highlighted the key role the two allies need to play in negotiations.

“To be successful in such an ambitious undertaking, our regional allies — in particular the Republic of Korea and Japan — are indispensable to our success,” it said, referring to South Korea’s formal name. “No concessions should be granted that could undermine our core alliance commitments or our posture in the region.”

In regards to the abductees, Tokyo officially recognizes 17 people as having been taken to North Korea in the 1970s and 1980s. Five were returned in 2002.

Japan believes Kim Jong Un will probably reassert during the summit with Trump that of the remaining 12 people, eight have died and the other four never entered North Korea, according to the sources.

Late Monday, the North’s official Korean Central News Agency hammered home Pyongyang’s stance, blasting Japan in a commentary for stressing the abductee issue.

“Japan is bound to be ridiculed by the international community and driven out of history if it persists in escalating confrontation with the DPRK under the pretext of the already resolved ‘abduction issue,’ failing to acclimatize itself to the new situation,” it said.

Abe, who views the issue as a government priority, will call on Trump to reject that assertion and try to persuade Kim to understand the necessity of Japan-North Korean consultations on the abduction issue, the sources said.

Japan has continued behind-the-scenes contacts with North Korea through multiple channels. Pyongyang admits a 2014 agreement reached in Stockholm is still in effect.

In 2014, Japan and North Korea agreed that Pyongyang would reinvestigate the fate of all of the abductees. But North Korea then disbanded the panel and effectively abandoned the bilateral agreement.