South Korea's foreign minister says Seoul has begun "contingency planning" to ensure that her country and Britain maintain close trade relations after Britain leaves the European Union.

Foreign Minister Kang Kyung-wha said Friday that "we are already having serious discussions about this."

She said South Korea's president held talks with British Prime Minister Theresa May about future trade ties on the sidelines of a summit of European and Asian leaders in Brussels.

South Korea's President Moon Jae-in arrives for an EU-ASEM summit in Brussels, Friday, Oct. 19, 2018. EU leaders meet with their Asian counterparts Friday to discuss trade, among other issues. (AP PhotoOlivier Matthys)

South Korea's President Moon Jae-in arrives for an EU-ASEM summit in Brussels, Friday, Oct. 19, 2018. EU leaders meet with their Asian counterparts Friday to discuss trade, among other issues. (AP PhotoOlivier Matthys)

EU foreign policy chief Federica Mogherini warned that Britain cannot negotiate or conclude trade agreements while it remains a EU member. That includes during any transition period.

May and her European counterparts have said they are open to a transition period after Britain leaves the EU on March 29 that could last anywhere from 21 months to about three years.

British Prime Minister Theresa May, right, speaks with European Council President Donald Tusk after a group photo an EU-ASEM summit in Brussels, Friday, Oct. 19, 2018. EU leaders met with their Asian counterparts Friday to discuss trade, among other issues. (AP PhotoAlastair Grant)

British Prime Minister Theresa May, right, speaks with European Council President Donald Tusk after a group photo an EU-ASEM summit in Brussels, Friday, Oct. 19, 2018. EU leaders met with their Asian counterparts Friday to discuss trade, among other issues. (AP PhotoAlastair Grant)