Foreign Minister Kang Kyung-wha called in Japanese Ambassador Koji Tomita on Friday to lodge a protest over Tokyo's decision to impose new entry restrictions for South Koreans over novel coronavirus fears.

Kang met Tomita hours after the ministry voiced "extreme regrets" over Japan's plan to request a two-week quarantine for visitors from South Korea.

Tokyo has announced that from Monday through the end of this month, visitors from South Korea and China will be asked to stay at designated facilities for two weeks and refrain from using public transportation. It also plans to suspend the 90-day visa-free entry program for South Koreans on Monday.

Japan has already banned the entry of people who have visited the southeastern city of Daegu and adjacent Cheongdo County, where the bulk of the country's COVID-19 infections have taken place.

Earlier in the day, the presidential office Cheong Wa Dae also expressed "strong regrets" over Japan's measures, after it convened a standing committee session of the National Security Council.

At the session, NSC members decided to weigh "necessary measures based on the principle of reciprocity."

The foreign ministry said that it is mulling "all possible" corresponding measures, while urging Tokyo to rethink the measures.

"We express extreme regrets over the fact that Japan has taken such an unreasonable and excessive measure without sufficient consultations with us, although our government has urged Japan to cautiously review its additional measures multiple times," the ministry said in a text message sent to reporters.

"We strongly urge Japan to immediately reconsider this measure," it added.

The ministry also raised doubts over Japan's intentions behind the latest step.

"Given that this measure came when signs of progress in our containment efforts appear to have emerged, we cannot help but doubt whether Japan has other intentions than its considerations of the quarantine aspect," the ministry said.

"While placing the top priority on the health and safety of our citizens, the government is weighing all possible measures (in response to Japan's measure)," it added.

Japan's latest restrictions angered South Korea in particular because Seoul has refrained from such extraordinary steps against Japanese nationals even at the onset of the outbreak on a virus-hit cruise ship off its coast.

Critics raised speculation that Tokyo might have decided to tighten restrictions on the entry of Koreans to help circumvent domestic criticism of Prime Minister Shinzo Abe's handling of the virus outbreaks.

As for the possible measures, observers said that Seoul could consider restricting the entry of people from Japan and halting the 90-day visa-free program for Japanese visitors.

But South Korea could face a dilemma, as it has not taken any tit-for-tat steps against the countries that have been enforcing entry bans or other forms of restrictions on Korean travelers.

In particular, Seoul did not take any action after Chinese provincial authorities quarantined some 860 South Koreans as precautions.

As of midnight, South Korea has reported 6,284 confirmed cases of the novel virus and 42 deaths. As of 10 a.m. Friday, 102 countries and territories planned to enforce or were imposing entry restrictions or stricter quarantine programs for people from South Korea. (Yonhap)