US President Donald Trump has said that his administration will have most of its trade deals with countries finished by August 1, as South Korea and other trading partners are striving to reach agreements to lower its "reciprocal" tariff rates by the negotiation deadline.

During a press availability at the White House, Trump also said his administration might send close to 200 countries a letter on their tariff rate, which he said means, "They have a deal. It's done."

South Korea has been cranking up its efforts to reach a deal with the United States to avoid or reduce the threatened 25 percent reciprocal tariffs, as well as sector-specific duties on automobiles and steel, as those levies would weigh heavily on the country's export-driven economy, said Yonhap news agency.

"Aug. 1 is going to come, and we will have most of our deals finished, if not all," Trump told reporters before embarking on a trip to Scotland.

"When those letters go out ... the page and a half ... That means they have a deal. It's done," he said. "They pay that tariff and that is the contract essentially."

US President Donald Trump's administration continues to have "productive" negotiations with South Korea to reduce "unfair" trade barriers and enhance market access for U.S. businesses, a White House official said.

South Korea has been making concerted efforts to reach a trade deal with Washington to reduce the threatened 25 percent "reciprocal" tariffs and sector-specific tariffs on steel and automobiles before August 1, when the reciprocal tariffs are set to take effect.

"We continue to have productive negotiations with South Korea to reduce unfair trade barriers and improve market access for American firms," the official told Yonhap News Agency via email.

The official's characterisation of the negotiations as "productive" raised cautious hope for headway in the trade talks, as Seoul has made proposals for bilateral cooperation in key strategic industry sectors, including shipbuilding, semiconductors and batteries.

On Thursday, South Korea's Industry Minister Kim Jung-kwan and Trade Minister Yeo Han-koo met jointly with U.S. Commerce Secretary Howard Lutnick in Washington as part of their efforts to reach a trade deal with the Trump administration.

Seoul's Finance Minister Koo Yun-cheol and Yeo had planned to have a "two-plus-two" meeting with Treasury Secretary Scott Bessent and U.S. Trade Representative Jamieson Greer in the U.S. capital on Friday, but the meeting was postponed due to a scheduling conflict on Bessent's part.

Earlier in the day, Trump said that his administration will have most of its trade deals with countries finished by Aug. 1.

The president also said his administration might send close to 200 countries a letter on their tariff rate, which he said means, "They have a deal. It's done."