The science ministry says it received a letter from the U.S. two weeks ago urging the implementation of follow-up measures to last November's joint fact sheet outlining agreements in the security and trade sectors.

The ministry revealed on Tuesday that the letter was sent in the name of James Heller, the Chargé d'Affaires ad interim at the U.S. Embassy in Seoul, and addressed to Science Minister Bae Kyung-hoon, who received it on January 13.

The ministry said similar letters were also sent to four other government agencies, but stopped short of providing any more details, saying it cannot give specifics on diplomatic issues. 

Following the South Korea–U.S. summit held in Gyeongju on October 29 of last year, the two sides released a joint fact sheet in November outlining agreements in the security and trade sectors, including South Korea’s commitment to invest 350 billion dollars in the U.S. in exchange for tariff reductions on South Korean goods and U.S. approval of its nuclear-powered submarine project.

Earlier on Monday, U.S. President Donald Trump said he would raise tariffs on South Korea back to 25 percent from the previous 15 percent, citing the South Korean National Assembly's failure to complete the legal procedures necessary to implement the bilateral trade deal.