WASHINGTON – As John Kerry yesterday stepped up his counterattack on President Bush by arguing that the GOP is pursuing a campaign of “fear and smear,” Vietnam veterans who served with the Massachusetts senator shifted their criticism of his war record and began focusing on the Democrat’s claims of involvement in several clandestine operations in Cambodia.

With the dust not settled on their previous charges that Mr. Kerry distorted his war experiences in order to win medals, including a Silver Star and three Purple Hearts, anti-Kerry vets alleged that the Democrat has falsely claimed to have ferried CIA operatives into Cambodia to search for enemy enclaves and to deliver weapons to anti-Communist forces.

The senator’s shipmates argue that Mr. Kerry is inflating his war record and they again challenged him to agree to a release of his full official military record so the discrepancies and differences in memory can be resolved. “I am certain he was never involved in clandestine operations in Cambodia,” retired Admiral Roy Hoffmann told The New York Sun.

The further questioning of Mr. Kerry’s war reminiscences failed to elicit a response from the Democrat’s campaign, which has already sought to clarify once past remarks the senator has made about being in Cambodia during his four-month tour of duty in Indochina between 1968 and 1969.That clarification came earlier this month but concerned a 1986 Senate speech in which Mr. Kerry spoke of spending Christmas Eve of 1968 in Cambodia, at the time officially a neutral country in the war raging in Indochina.

In that speech, Mr. Kerry said: “I remember Christmas of 1968 sitting on a gunboat in Cambodia. I remember what it was like to be shot at by the Vietnamese and Khmer Rouge and Cambodians, and have the president of the United States telling the American people that I was not there; the troops were not in Cambodia. I have that memory which is seared – seared – in me… .”

The Kerry campaign has quietly suggested that their candidate may have misspoken when claiming to have been in Cambodia over the Christmas of 1968, but they have refused to budge from the Massachusetts senator’s past statements of being in Cambodia several times on clandestine missions.

Michael Meehan, a spokesman for the campaign, insisted in a statement issued earlier this month that “many times” Mr. Kerry “was on or near the Cambodian border and on one occasion crossed into Cambodia at the request of members of a special operations group operating out of Ha Tien.”

According to Admiral Roy Hoffmann, who was in overall command in 1969 of the Swift boats based in the Mekong Delta, Mr. Kerry was never involved in clandestine operations in Cambodia. He characterizes as fiction the Senator’s claims over the years that he was. “I would have been informed of any such CIA operations or incursions by Special Forces into Cambodia involving Swift boats and at the time there were none,” Admiral Hoffman told the Sun.

The admiral, who was commander of Coastal Surveillance Force Vietnam and is a leading member of the anti-Kerry group Swift Boat Veterans for Truth, says that he has no recollection of any Swift boat-related clandestine intelligence operations into Cambodia in the winter of 1969. “In fact, we were very careful to avoid them after some Army logistics people had inadvertently crossed into Cambodia territory and it took a massive diplomatic effort from the Canadians and Australians to get them out,” he says.

A fellow member of the Swift Boat Veterans for Truth, retired Captain John O’Neill, has also disputed Kerry’s account but again focused only on the Kerry Christmas recollection. In his best-seller “Unfit for Command,” Mr. O’Neill wrote: “Preventing border crossings was considered so important at that time that an LCU (a large, mechanized landing craft) and several PBRs (smaller patrol boats) were stationed to ensure that no one could cross the border. A large sign at the border prohibited entry.”

Mr. Kerry’s recollections are different. He has referred to several clandestine missions into Cambodia. In 2003,he told the Washington Post that he carried a battered old hat in his briefcase, saying that it was his “good luck hat…Given to me by a CIA guy as we went in for a special mission in Cambodia.”

The Kerry campaign failed to return calls from the New York Sun seeking a response to allegations disputing the Democrat’s Cambodia recollections.

On at least eight occasions, either while speaking in the Senate or to the press, the senator has referred to taking part in multiple clandestine operations in Cambodia.

As the dispute waged yesterday over Mr. Kerry’s reminiscences, Admiral Hoffman confirmed to the New York Sun that Mr. Kerry on Sunday night phoned another Swift boat veteran, retired Commander Robert Brant, who is opposed to his presidential candidacy. In the call, the senator said he wanted a face-to-face meeting with anti-Kerry vets.