America's trading partners are reacting with frustration to U.S. President Donald Trump's latest tariff threats, after months of what they believed were good-faith efforts to make a deal.

The European Union may be nearing a trade agreement with the United States but is struggling to obtain immediate tariff relief and a commitment not to introduce new measures, the head of the European Parliament's trade committee said on Wednesday.

"I see that there might be a corridor for some understanding in the tariff situation on steel, on cars and, of course, also regarding some possible exceptions from the baseline tariffs," said German Social Democrat Bernd Lange, who is not part of the EU's negotiating team but is in touch with those involved.

The European Commission, which has been negotiating on behalf of the 27-nation bloc, is pushing to reach a framework agreement with the United States by August 1.

It currently faces 50 percent U.S. tariffs on its steel exports, 25 percent on cars and a broad 10 percent tariff on most other exports. A 50 percent tariff on imported copper is imminent, with levies due soon for semiconductors and pharmaceuticals.

The tariffs are not acceptable for the EU, Lange said, as they target the bloc's industrial development.

Lange said the main issues in negotiations for the EU were to secure lower tariffs at the point of reaching a framework agreement, rather than waiting weeks or months for a final accord, and a "stand-still clause" meaning it would not face further measures.

South Korea's trade ministry said on Tuesday that it will make efforts to achieve a mutually beneficial trade deal with the United States following Trump's effective extension of the pause on new tariffs on South Korean products.

The Ministry of Trade, Industry and Energy said in a statement that Seoul had been engaged in fierce negotiations under the principle of putting top priority on national interests since the inauguration of the new government under President Lee Jae-myung, who took office on June 4.

The ministry noted that there was not enough time to reach an agreement on all issues, considering Trump's letter an effective extension of the pause on "reciprocal" tariffs on South Korean products.

It vowed to step up efforts to reach a mutually beneficial negotiation outcome in the remaining period to rapidly resolve uncertainties arising from tariff issues, saying that the Asian country will tackle the U.S.'s major concern surrounding trade deficit issues through improved domestic rules and rationalized regulations.

Japanese Prime Minister Shigeru Ishiba warned on Tuesday that Trump's decision to impose a 25 percent tariff on Japan is "truly regrettable," adding that negotiations will continue toward a mutually beneficial deal.

"We will continue to engage in negotiations with the United States to explore the possibility of reaching a mutually beneficial deal while protecting our national interests," Ishiba told the meeting.

The United States will impose 25 percent tariffs on imports from Japan, starting August 1, Trump said on Monday, warning that any increases to the tariffs on U.S. goods will be met with an equivalent tariff hike by his administration.

The U.S. president also announced new tariff rates for 13 other countries on the same day, including 25 percent for South Korea, 30 percent for South Africa, 35 percent for Serbia and Bangladesh, 36 percent for Thailand and Cambodia, and 40 percent for Myanmar and Laos.

(With input from agencies)