South Korea will send a vice foreign minister to the Chinese Embassy's event this week to celebrate the 25th anniversary of diplomatic ties, the foreign ministry said Tuesday, amid a row over the ongoing installation of a US missile defense system in South Korea.

"Vice Foreign Minister Lim Sung-nam will join the South Korean-based Chinese Embassy's reception in place of the foreign minister and give a celebratory speech there," ministry spokesman Cho June-hyuck said in a press briefing.

"Vice Minister Lim will reaffirm his commitment to step up the bilateral relationship and cooperation for peace and stability in the Northeast Asian region," Cho said.

The embassy is scheduled to celebrate the 25th anniversary of the establishment of official South Korea-China diplomatic ties with an event on Thursday at a Seoul hotel.

South Korean Foreign Minister Kang Kyung-wha plans to leave for Russia on the same day for a meeting with her Russian counterpart Sergey Lavrov set for Friday in Moscow, without attending the embassy function.

The spokesman said that the South Korean and Chinese foreign ministers will send a message of congratulations on the occasion of the anniversary.

The relatively subdued festivity this year compares with the countries' marking of their 20th anniversary in 2012 when then-South Korean Foreign Minister Kim Sung-hwan attended a similar Chinese Embassy event in Seoul.

A government source said Kang's absence has nothing to do with the current bilateral feud as her visit to Russia had already been set up, but the ongoing friction apparently seems to be playing a part.

Diplomatic ties between the two neighboring countries have been put to the test as the two remain staunchly at odds over the ongoing installation of a US missile defense system in South Korean territory. In July last year, South Korea and the US unveiled their plan to install a Terminal High Altitude Area Defense battery, saying that it is intended to better defend against missiles from North Korea.

China has adamantly opposed the move, claiming it is part of the US missile defense network and its powerful X-band radar, in particular, will hurt its strategic security interests.

The source also said Chinese Foreign Minister Wang Yi is unlikely to attend the anniversary event organized by the South Korean Embassy in Beijing. It is still unknown who will represent China at the event, the source said.

In 2012, then-Chinese Vice President Xi Jinping and Foreign Minister Yang Jiechi attended the embassy event in Beijing. Xi and Yang are now the country's president and state councilor. (Yonhap)