Top diplomats from South Korea and the United States are expected to meet in Washington just before the Donald Trump administration's 25-percent reciprocal tariff takes effect on August 1.

According to diplomatic sources on Friday, Foreign Minister Cho Hyun and U.S. Secretary of State Marco Rubio practically agreed to meet at around midnight on July 31, Korea time.

Seoul and Washington's ongoing tariff negotiation could either have been settled by the time of the ministerial talks, or in the midst of an eleventh-hour tug-of-war.

Other key issues that will likely feature on the ministerial agenda include the Trump administration's call for its allies to raise their defense spending, as well as a summit between President Lee Jae Myung and U.S. President Trump.