When House members are invited by a private group to travel overseas at the organization's expense, they often make two calls to ensure the trip is proper.

As some two dozen congressional offices are now learning, checking with the House ethics (search) committee and the organization paying the bill isn't enough. They need to contact a Justice Department office that registers foreign agents.

At least eight House members and 15 House aides accepted trips to South Korea from a registered foreign agent despite rules prohibiting the practice, government documents show. Lawmakers said they didn't know the Korea-United States Exchange Council had registered as an agent of the South Korean government.

"It's a great 20-20 hindsight story," said Michael DeCesare, spokesman for Rep. James McDermott, D-Wash., who went on one of the group's trips. McDermott's understanding, DeCesare said, "was that the ethics committee cleared this."

Majority Leader Tom DeLay (search), R-Texas, and an aide to Democratic leader Nancy Pelosi (search), D-Calif., were among those traveling at the expense of the council, which registered as a foreign agent on Aug. 22, 2001.

The Pelosi aide, Eddie Charmaine Manansala, took a trip sponsored by the council from June 26, 2004, through July 3, 2004, but only filed the required disclosure form with the House on Wednesday.

A spokeswoman for Pelosi, Jennifer Crider, said Manansala forgot to file her form last year and did so after receiving a query from a reporter. The Washington Post reported on the trips in Thursday's editions.

The council describes itself as a nonpartisan, not-for-profit group that provides insight on the national security, cultural, historical and economic interests of the United States and South Korea. The council said in a statement Thursday its registration as a South Korean agent may have been a mistake.

The organization received $103,637 before its registration, according to its Justice Department public filing. In subsequent filings through 2002, the council listed no other amounts received.

The council took the blame for any problems. In its statement Thursday, it assured lawmakers the trips "met with the approval of the House Committee on Standards of Official Conduct, as we believed to be the case." The statement referred to the ethics committee's formal name.

The statement, issued by assistant secretary Edward Stewart, said the organization is examining whether the registration as a foreign agent "was ever appropriate" for a public charity under the Internal Revenue Code.

House rules say members may not accept travel from a registered lobbyist or agent of a foreign principal. Federal law requires that individuals, groups or corporations who receive financial support from foreign governments, political parties or individuals for the purpose of influencing U.S. opinion or policies register with the Justice Department.

House members taking trips paid for by the council, since the registration, included DeLay; McDermott; Earl Pomeroy, D-N.D.; Eni Faleomavaega, D-American Samoa; Michael Honda, D-Calif.; Ileana Ros-Lehtinen, R-Fla.; Ander Crenshaw, R-Fla., and John Carter, R-Texas.

The 15 aides included staff members from offices other than those of the eight lawmakers.

Dan Allen, DeLay's spokesman, said the council registered as a foreign agent only days before DeLay, Ros-Lehtinen and Crenshaw took their trip.

"When the invitation was extended and the trip planned, they were not registered," Allen said. "They never informed us of that change. The group was representing to members that they had the approval from the ethics committee."

Lisa Williams, chief of staff to Faleomavaega, said the lawmaker "went through the process of clearing himself with the ethics committee."

Gretchen Hamel, spokeswoman for Carter, said the council "told us everything was approved through ethics." She said Carter's staff also contacted the ethics committee and received approval.

"Congressman Carter just became aware late last night (Wednesday) that the Korea-United States Exchange Council was in violation of House ethics," Hamel said. "As a former judge, he makes sure he abides by all standards and ethics."

Alex Cruz, spokesman for Ros-Lehtinen, said the congresswoman was unaware of the foreign agents registration. Kenneth Lundberg, spokesman for Crenshaw, said, "We did an internal review. There were no flags of any kind."