WASHINGTON – A federal investigation was urged yesterday into allegations that a South Korean intelligence operative assisted in raising funds for the Kerry campaign from Asian-Americans.

The South Korean Embassy refused last night to comment on the claims that Chung Byung-Man, a consular official in Los Angeles until his recall in May, paired with Atlanta businessman Rick Yi, a retired American Army major, to solicit tens of thousands of dollars in donations in California for the Kerry campaign.

“We cannot comment on any of this,” an embassy official told The New York Sun.

Earlier, however, an official of the Seoul government’s consulate in Los Angeles conceded to the Associated Press that Mr. Chung, while ostensibly a consular official, worked for South Korea’s National Intelligence Service.

“According to international tradition, we cannot identify, we cannot say who he is, because he is intelligence people,” the spokesman, Min Ryu, said.

American officials, speaking on condition of anonymity, confirmed that Mr. Chung does work for South Korea’s intelligence service. They would not comment further when asked whether the FBI had mounted an investigation into his activities in California.

Both the Justice Department and the State Department declined to comment on Mr. Chung.

“Why was the South Korean government sending over an intelligence operative to meet with Kerry campaign people and talk with them about raising money? There should be an investigation to find out what was happening here,” a spokesman for the Center for Public Integrity, William Allison, told the Sun.

Mr. Chung’s involvement in the Kerry campaign is said to have surprised some Korean-Americans in Los Angeles whom he introduced to Mr. Li. The latter raised about $500,000 for the Kerry campaign.

A Kerry spokesman, Chad Clanton, said the campaign did not know that Mr. Chung was an intelligence agent or that Mr. Yi, one of the Democratic presidential nominee’s key fund-raisers in the Asian-American community, was meeting with Mr. Chung regularly and had secured his help in fund-raising.

Kerry campaign officials became concerned about Mr. Li’s activities last spring when questions arose about the immigration status of some of the Korean-Americans who were donating to the campaign through him. Under federal election laws, only American citizens or legal residents may contribute to political campaigns.

In the spring, Kerry officials returned two donations of $2,000 each from South Koreans.

One of those donors, Chun Jae-yong, is the son of a former South Korean president. Mr. Chun, who was a partner with Mr. Yi in a business venture in Georgia, was arrested last winter by South Korean authorities and charged with evading taxes.

Mr. Li, who started fund-raising for Senator Kerry last year, resigned from the campaign in May amid recriminations over Mr. Chun’s donation. At the time Mr. Yi said he “didn’t think anything was wrong with accepting the donation.”

Mr. Chung left the States shortly after.

According to Mr. Li, Mr. Chung discussed with him forming a political group, to be called the Korean-American Leadership Council, to organize influential Korean-Americans.” He asked me to spearhead this council,” Mr. Li said, according to AP. “I rejected his proposal because I didn’t have time.”

He said: “I asked him, ‘Is this appropriate for a diplomat to do?’ He said he was only starting this up because there were no Korean-Americans to do it. Once two or three candidates were identified, he would hand it over.”

The allegations of the involvement of South Korean intelligence in raising money for the Democrats came only hours after the chairman of the defense committee in South Korea’s National Assembly surprised American diplomats in Seoul by publicly stating it would be better for his country if Mr. Kerry defeats President Bush in November. Mr. Kerry would be “better at resolving a nuclear standoff with Pyongyang through dialogue,” Yoo Jay-kun said.

Last night, the Korean intelligence service dismissed, as a “totally groundless rumor and all fiction,” suggestions that the Seoul government had tried to influence the American election.

But Mr. Allison, of the Center for Public Integrity, said Mr. Chung’s role needed a thorough investigation by American authorities.

“When you get a foreign intelligence agent involving themselves in U.S. politics like this, there should be a probe,” he said. “While the Kerry campaign appears to have done the right thing in returning suspect donations, there are unanswered questions.”

Both the Democrats and Republicans have increased their vetting of fund-raisers and donors since the late 1990s, after a Clinton fundraising scandal led to questions about whether the Chinese government had attempted to influence the 1996 presidential race.

Kerry campaign aides say they seek to check backgrounds to ensure that donors are either American citizens or legal residents.

In the late 1990s, Mr. Kerry returned suspect donations from Johnny Chung, a key figure in that fund-raising scandal.