President Trump said "progress" is being made during his nearly two-week trip across Asia, claiming the president of China is starting to tighten sanctions against North Korea.

"President Xi of China has stated that he is upping the sanctions against #NoKo. Said he wants them to denuclearize. Progress is being made," Trump tweeted early Sunday, Vietnam time.

Trump has been making moves to tighten sanctions on North Korea since he stepped into office, he signed an executive order this summer aimed at cutting North Korea out of the international banking system. Trump also gave orders to widen the range for blacklisting those doing business with North Korea.

He met with Xi in China last week, and both attended the APEC meeting in Vietnam this weekend.

Also part of Trump's strategy to convince Pyongyang to end its nuclear and missile programs is pushing China, North Korea's neighbor to the north, to pressure North Korean leader Kim Jong Un to lay off.

South Korean President Moon Jae-in's spokesman said that he and Xi agreed to navigate the North Korean issue peacefully, according to a Reuters report, as they met along the sidelines of APEC.

There was no mention of new sanctions in the report, but Beijing has said it has been complying with United Nations sanctions against North Korea.