WASHINGTON (AP) _ The government will fight prosecutor Kenneth Starr's pursuit of President Clinton's Secret Service detail, including the head of the elite team, to testify in the Monica Lewinsky investigation.

A government official told The Associated Press that the Justice Department would challenge the subpoenas in court as early as today. Such an attempt to block grand jury testimony from the Secret Service probably would be sealed.

Starr also subpoenaed six uniformed officers and demanded that the agency turn over documents detailing the president's nighttime whereabouts from 1995 through 1997, the years Ms. Lewinsky was in Washington as a White House intern and a Pentagon staffer.

Although the Secret Service subpoenas are for Thursday, continuing testimony from one of Starr's chief witnesses, Linda Tripp, could take the entire day.

Starr's move to question Special Agent Larry Cockell and others in the Secret Service is being vigorously resisted by the administration. On Tuesday the Justice Department filed new appeals of court decisions that declared the prosecutor is entitled to evidence from the agency sworn to protect the president.

Three government officials confirmed the subpoena was issued to Cockell. Legal sources confirmed the subpoenas to the four uniformed officers. All spoke on condition of anonymity.

The Justice Department is seeking a review by the full U.S. Court of Appeals of the District of Columbia Circuit of the ruling of a week ago by three appeals court judges.

Among those subpoenaed was uniformed Secret Service officer Gary Byrne, one of three Secret Service employees involved in the court case.

Starr and the Clinton administration are embroiled in a high-stakes court battle to determine whether Secret Service employees can be compelled to divulge what they observe while protecting the president.

Though the issue could be delayed for some time if the full appeals court takes the case, Starr pressed ahead with his investigation to see whether Secret Service agents have relevant information about whether the president had a sexual relationship with Ms. Lewinsky and tried to cover it up.

The subpoena to Cockell sent shock waves through the Secret Service and left officials concerned that subpoenas would be sent to other former heads of Clinton's personal detail, including Lewis Merletti, David Carpenter and Brian Stafford, one official said.

Merletti is the director of the Secret Service. Carpenter, a tall gray-haired agent often mistaken for Clinton, left the agency and has been appointed by the president to head the State Department's security team and the office of foreign missions. He is awaiting Senate confirmation to the prestigious post, which carries the rank of ambassador.

A third government official, speaking on condition of anonymity, said Carpenter had not been subpoenaed, and he has not talked to Starr or his office.

Secret Service officials were worried that Starr's actions might have a chilling effect on the relationship between Clinton and his immediate security detail. The president and the detail headed by Cockell will travel to Arkansas and Louisiana this weekend.

Starr's staff advised the Justice and Treasury departments some time ago that they wanted to subpoena additional Secret Service personnel in the Lewinsky case, a senior Justice official said.

This official said Starr's staff felt that, having won two court decisions, they were entitled to deliver those subpoenas now.

One of the government officials also confirmed that Starr has subpoenaed records from the Secret Service that would detail Clinton's activities and whereabouts at night on numerous dates between 1995 and 1997. CBS News first reported the request.

After being transferred to the Pentagon, Ms. Lewinsky returned to the White House on more than three dozen occasions for visits, mostly to the Oval Office.

In its appeal, the administration argued that the three-judge appeals panel wrongly ``substituted its judgment'' for the judgment of experienced Secret Service officers and agents.

``As the Secret Service has explained in no uncertain terms, the life of the president may turn upon recognition'' of a new privilege for agents who protect the president, the Justice Department's latest brief said.

The appeal was filed as chief witness Linda Tripp spent a fifth day testifying before a grand jury. Mrs. Tripp's tape-recorded conversations with Ms. Lewinsky triggered the investigation into possible perjury and obstruction of justice.

Six of the full appeals court's 11 judges would have to agree for the case to be reconsidered. If the full appeals court does not rehear the case, the Justice Department could ask the Supreme Court to consider it. But the high court does not return from its summer recess until October.