SEOUL - South Korea's presidential security adviser headed to Washington on Sunday for trade and defense talks as Seoul discussed an extension of the freeze on US tariffs that is set to expire within days.

Wi Sung-lac, President Lee Jae-myung's national security adviser, aims to meet his counterpart, US Secretary of State Marco Rubio. "Consultations are now entering an important phase. Therefore, I am increasing engagement on my side," Wi said of the trade and defense talks without elaborating.

ALSO READ: South Korea’s point man on trade to seek later tariff deadline

US President Donald Trump has previously said that defense cost-sharing would be part of "one-stop shopping" negotiations with South Korea, though Seoul has said security issues were separate from trade discussions.

Wi plans to "have in-depth discussions about all the pending issues between South Korea and the United States" in Washington over July 6-8, Wi's office said in a statement.

He also said he plans to discuss a possible summit between Trump and Lee, who took office last month.

Tariff pause extension

South Korean trade minister Yeo Han-koo and US counterpart Jamieson Greer on Saturday discussed an extension of the freeze on US tariffs that is set to expire within days, South Korea's trade ministry said.

Yeo emphasised that elimination or reduction of tariffs on autos, steel and other items should be part of a final agreement between the two countries while proposing a vision for cooperation in manufacturing sectors, the ministry said.

READ MORE: Lee says unsure S. Korea can land US trade deal by deadline

"I believe the situation is urgent," Yeo told reporters during his second visit to Washington within a week.

Yeo expected Trump to again suspend the higher tariffs that he has threatened to impose from Aug 1 after his July 9 deadline ends.