A senior U.S. diplomat has called North Korea's announcement to stop nuclear and missile tests a "very positive" step.

Susan Thornton, acting U.S. assistant secretary of state for East Asian and Pacific Affairs, made the remarks on Sunday afternoon upon her arrival at Incheon International Airport. 

The U.S. official noted that North Korea had already said they would stop tests, but it's a good sign that they are saying it again.

She added the U.S. will closely consult and coordinate with South Korea, its allies and partners this week.

Thornton, who is in charge of working-level preparations for the U.S.-North Korea summit, is set to hold talks with South Korean Foreign Minister Kang Kyung-wha and Assistant Foreign Minister Yoon Soon-gu on Monday.

She will then meet with Seoul's top nuclear envoy Lee Do-hoon on Tuesday. Lee is also scheduled to meet with his Japanese counterpart Kenji Kanasugi on Monday. 

During the meetings, Thornton and the Seoul officials are expected to have in-depth discussions to coordinate the positions of the two nations regarding the North's denuclearization and the establishment of a peace regime on the Korean Peninsula, ahead of the inter-Korean summit set for Friday.

The two sides are likely to share their assessments on and discuss their responses to Pyongyang's announcement on Saturday, that it would halt nuclear and missile tests and shut down its nuclear test site.

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