North Korea and China have been celebrating their friendly relations on major anniversaries with letter exchanges and a banquet, South Korea’s unification ministry said Monday, with the two sides unable to send delegations due to COVID-19.

Ministry spokesperson Lee Jong-joo said that the countries have shown a “trend” of emphasizing their relationship lately, as they stress their shared awareness of the “current international situation” and seek to underscore the importance of a “mutual response.” This has included their celebration of the 60th anniversary of the China-DPRK friendship treaty.