The document directed banks to explain to any North Korean customers that "our bank is fulfilling our global obligations and implementing United Nations sanctions against North Korea".
A third United States official said the USA expects North Korea to carry out additional tests on its intercontinental ballistic missile now that its intermediate range ballistic missile has proven its success.
Warren said her view is that there is no "military-only" solution in North Korea.
What has North Korea said?
Chinese President Xi Jinping and U.S. President Donald Trump spoke about keeping pressure on North Korea using economic sanctions imposed through the United Nations, the White House said on Monday. The country is said to be developing missiles that could reach the U.S.
The sanctions also ban the sale of natural gas liquids to the North Korea, as well the imports of any textile products such as fabrics and apparel products from North Korea.
The fresh measures followed the sixth and most powerful nuclear test conducted by Pyongyang earlier this month.
"As such, we refuse to handle any individual loans connected to North Korea".
The official Chinese news agency Xinhua said that Russian Federation and China began naval exercises near the eastern port of Vladivostok.
How is the world responding?The country's new liberal President Moon Jae-in, who took office in May, has maintained that the issue of providing humanitarian aid to North Korea should be handled independently from political circumstances.
A slim majority of Americans do not trust President Donald Trump to handle the ongoing conflict with North Korea. "We should think not about military methods but how to start talks and dialogue", he said.
Mattis was also asked whether he believed the newest United Nations sanctions against Pyongyang were working.
"They [China] don't think we are really honest about military action".
South Korea's on the very front line.
Tensions between the USA and North Korea have steadily moved toward a boiling point, especially after North Korea exercised its strongest nuclear test yet on September 3.
He called Kim a "rocket man on a suicide mission" as he condemned the rogue nation's most recent wave of missile tests. The move follows similar decisions by Peru and Mexico and comes after the USA urged worldwide action against the country.
The United States, South Korea and Japan carried out military exercises with warplanes over the Korean Peninsula Monday.