Officials of the White House and the State Department have met secretly with two elderly Korean victims of Japan's wartime sexual enslavement of women, sources said Tuesday, an unprecedented move that suggests Washington's policy on the issue may change.

The two -- Lee Ock-sun, 87, and Kang Il-chul, 86 -- met with White House officials last Tuesday before holding a meeting with State Department officials the following day, the sources said. It was the first time that White House and State Department officials have held such meetings.

The meetings, which lasted about an hour each, were set up at the request of U.S. officials. The two women were unaccompanied in the meetings as requested by U.S. officials, the sources said. U.S. officials also brought interpreters to the meetings, they said.

Further details were not available, including what they discussed.

The unprecedented meetings have spurred speculation that the U.S. could change its policy or try to broker a resolution to the issue, the biggest thorn in relations between South Korea and Japan. Frayed ties between the two U.S. allies have hurt Washington's efforts to forge three-way security cooperation.

Lee and Kang have been on a visit to the U.S. since last month.

On Monday, the two attended a ceremony to unveil an additional monument in the U.S. state of New Jersey in memory of sexual slavery victims.

The monument, set up at the Liberty Plaza in Union City, is the seventh such memorial erected in the United States. On top of the stone monument is a butterfly sculpture symbolizing the victims, known euphemistically as "comfort women."

About 400 people attended the ceremony, including Union City Mayor Brian Stack.

"We don't have enough power to resolve this ourselves," Lee said during the ceremony, criticizing Japan for denying that it coerced women into sexual slavery and arguing that they went voluntarily to make money.

"That is why I am here and have come all the way to the United States, because Japan is not listening to our demands and is making objections to the memorials that are being placed in the United States. I would like to ask for your help to resolve this as soon as possible," she said.

Kang said she is very grateful for the monument.

The six earlier "comfort women" monuments in the United States were erected in the states of New Jersey, New York, California and Virginia.

Historians estimate that up to 200,000 women, mainly from Korea and China, were forced to work at front-line brothels for Japanese soldiers during World War II. Korea was a colony of Japan from 1910 to 1945.

South Korea has urged Japan to resolve the grievances of the victims, saying the issue is becoming increasingly urgent as most victims are well over 80 years old and may die before they receive compensation or an apology from Japan.

But Japan has claimed that all issues related to its colonial rule of the Korean Peninsula were settled through a 1965 treaty that normalized their bilateral ties. (Yonhap)