President Park Geun-hye said Monday that Japanese Prime Minister Shinzo Abe has been under fire in the United States for his failure to properly apologize for Japan's wartime sex slavery.

South Korea and Japan have long been at odds over their shared history, including the Japanese military's sexual enslavement of Korean women during World War II.

Japan did not "face up to history," Park said in her first meeting with her top aides since she returned to work after a weeklong absence caused by fatigue from her recent South American tour.

Her criticism came days after Abe failed to apologize for Japan's wartime sex slavery in a speech to the Congress. The speech marked the first time that a Japanese prime minister has addressed a joint meeting of the House and the Senate.

Abe said that Japan's wartime actions brought suffering to Asian people, a comment that drew criticism from some U.S. lawmakers.

Rep. Mike Honda, who has championed sexual slavery victims, said it is shocking and shameful that Abe continues to evade Japan's responsibility over the so-called "comfort women" during World War II.

Abe's refusal to apologize is an "insult" to victims and is not acceptable, he said.

South Korea has repeatedly pressed Japan to resolve the issue of the elderly Korean women who were forced into sexual slavery for Japanese soldiers during World War II. Japan ruled the Korean Peninsula as a colony from 1910-45.

Park called on officials to clearly handle the past history.

Historians estimate that more than 200,000 women were forced to work in front-line brothels for Japanese soldiers during World War II. But Japan has long attempted to water down the atrocity.

Park also called on the government to improve a system for special pardons to ensure fairness and transparency.

In South Korea, presidents usually grant special pardons in commemoration of major national holidays, though the practice has long been under fire for being abused to give favors to their friends and business leaders jailed for corruption.

Park's comments came amid controversy over two previous special pardons granted on a businessman at the center of a bribery scandal.

Before hanging himself last month, the businessman, Sung Wan-jong, left behind a memo listing the names of the then prime minister and seven other high-profile politicians he claimed to have bribed. All but one listed on the memo are close associates of the president.

The prime minister has since quit and Park has called for a thorough probe into the scandal.

Park also said a recent deal by the rival political parties on pension reform for civil servants fell short of public expectation.

The rival parties have agreed to pass a bill on Wednesday that would require civil servants to pay more into and receive less in pension over the next two decades.

South Korea's civil service pension has long faced a looming crisis and caused a deficit of 12 trillion won every year until last year.

Previous presidents have delayed addressing the issue, despite knowing the current system is unsustainable. (Yonhap)