South Korea can expand its support to Ukraine, going beyond humanitarian and economic assistance, in the event of large-scale attacks on the civilian population, the country's president Yoon Suk-yeol said.

"If there is a situation the international community cannot condone, such as any large-scale attack on civilians, massacre or serious violation of the laws of war, it might be difficult for us to insist only on humanitarian or financial support," Yoon said in an interview with Reuters.

It was the first time that Seoul suggested a willingness to provide weapons to Ukraine, more than a year after ruling out the possibility of lethal aid.

Yoon said his government has been exploring how to help defend and rebuild Ukraine, just as South Korea received international assistance during the 1950-53 Korean War.

Yoon is due to visit Washington next week for a summit meeting with U.S. President Joe Biden.