South Korea's ruling party said on Thursday it would include up to 300 billion won (254.8 million U.S. dollars) in an extra budget to cope with Japan's recent export curbs on high-tech materials.

The Democratic Party said in a statement the budget would be intended to support South Korea’s own technology development and commercialization of items of which the country has relied on imports from Japan.

Japan tightened curbs last week on exports of three materials crucial for smartphone displays and chips, saying trust with South Korea had been broken over a dispute with Seoul over South Koreans forced to work for Japanese firms during World War Two.

Japan's export curbs are "undesirable" for trilateral cooperation

In a phone call with U.S. Secretary of State Mike Pompeo late on Wednesday, South Korean Foreign Minister Kang Kyung-wha said that Japan's trade restrictions may not only cause damage to South Korean companies but could also disrupt the global supply chain and hurt U.S. companies.

Kang "expressed concern that this is undesirable in terms of friendly relations between South Korea and Japan and trilateral cooperation among South Korea, the U.S. and Japan.”

Pompeo "expressed understanding" and both agreed to continue to cooperate and to strengthen communication between the three sides, according to a statement of the Foreign Ministry.

Kim Hyun-chong, deputy chief of South Korea's National Security Office, arrived in Washington, D.C., on Wednesday in an unannounced visit and told reporters he was there to meet officials from the White House and Congress to discuss issues that included Japan's export curbs.

Seoul hoped Tokyo would withdraw the curbs and that the situation would not deteriorate further, the Foreign Ministry said.

Read more: South Korea warns of 'prolonged' export row with Japan

(With input from Reuters)